diff --git a/prisma/mysql-migrations/20261029040337_add_label_instance_unique_key/migration.sql b/prisma/mysql-migrations/20261029040337_add_label_instance_unique_key/migration.sql
new file mode 100644
index 0000000000..f0c51abc10
--- /dev/null
+++ b/prisma/mysql-migrations/20261029040337_add_label_instance_unique_key/migration.sql
@@ -0,0 +1,2 @@
+-- CreateIndex
+CREATE UNIQUE INDEX `Label_labelId_instanceId_key` ON `Label`(`labelId`, `instanceId`);
diff --git a/prisma/mysql-schema.prisma b/prisma/mysql-schema.prisma
index 255c195dc4..debbad1b18 100644
--- a/prisma/mysql-schema.prisma
+++ b/prisma/mysql-schema.prisma
@@ -250,6 +250,8 @@ model Label {
   updatedAt    DateTime  @updatedAt @db.Timestamp
   Instance     Instance  @relation(fields: [instanceId], references: [id], onDelete: Cascade)
   instanceId   String
+
+  @@unique([labelId, instanceId])
 }
 
 model Proxy {
diff --git a/src/api/integrations/channel/meta/whatsapp.business.service.ts b/src/api/integrations/channel/meta/whatsapp.business.service.ts
index 098654c2d0..33d3a4e730 100644
--- a/src/api/integrations/channel/meta/whatsapp.business.service.ts
+++ b/src/api/integrations/channel/meta/whatsapp.business.service.ts
@@ -23,6 +23,7 @@ import { Events, wa } from '@api/types/wa.types';
 import { AudioConverter, Chatwoot, ConfigService, Database, Openai, S3, WaBusiness } from '@config/env.config';
 import { BadRequestException, InternalServerErrorException } from '@exceptions';
 import { createJid } from '@utils/createJid';
+import { jsonPath } from '@utils/jsonPath';
 import { status } from '@utils/renderStatus';
 import { sendTelemetry } from '@utils/sendTelemetry';
 import axios from 'axios';
@@ -864,7 +865,7 @@ export class BusinessStartupService extends ChannelStartupService {
               where: {
                 instanceId: this.instanceId,
                 key: {
-                  path: ['id'],
+                  path: jsonPath('id'),
                   equals: key.id,
                 },
               },
diff --git a/src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts b/src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts
index 22839fd451..328c2be4b3 100644
--- a/src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts
+++ b/src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts
@@ -85,6 +85,7 @@ import { createId as cuid } from '@paralleldrive/cuid2';
 import { Instance, Message } from '@prisma/client';
 import { createJid } from '@utils/createJid';
 import { fetchLatestWaWebVersion } from '@utils/fetchLatestWaWebVersion';
+import { jsonPath } from '@utils/jsonPath';
 import { makeProxyAgent, makeProxyAgentUndici } from '@utils/makeProxyAgent';
 import { getOnWhatsappCache, saveOnWhatsappCache } from '@utils/onWhatsappCache';
 import { status } from '@utils/renderStatus';
@@ -4184,7 +4185,7 @@ export class BaileysStartupService extends ChannelStartupService {
   }
 
   public async getLastMessage(number: string) {
-    const where: any = { key: { path: ['remoteJid'], equals: number }, instanceId: this.instanceId };
+    const where: any = { key: { path: jsonPath('remoteJid'), equals: number }, instanceId: this.instanceId };
 
     const messages = await this.prismaRepository.message.findMany({
       where,
@@ -4271,7 +4272,7 @@ export class BaileysStartupService extends ChannelStartupService {
         if (messageId) {
           const isLogicalDeleted = configService.get<Database>('DATABASE').DELETE_DATA.LOGICAL_MESSAGE_DELETE;
           let message = await this.prismaRepository.message.findFirst({
-            where: { key: { path: ['id'], equals: messageId } },
+            where: { key: { path: jsonPath('id'), equals: messageId } },
           });
           if (isLogicalDeleted) {
             if (!message) return response;
@@ -4691,7 +4692,7 @@ export class BaileysStartupService extends ChannelStartupService {
           const messageId = messageSent.message?.protocolMessage?.key?.id;
           if (messageId && this.configService.get<Database>('DATABASE').SAVE_DATA.NEW_MESSAGE) {
             let message = await this.prismaRepository.message.findFirst({
-              where: { key: { path: ['id'], equals: messageId } },
+              where: { key: { path: jsonPath('id'), equals: messageId } },
             });
             if (!message) throw new NotFoundException('Message not found');
 
@@ -5329,10 +5330,10 @@ export class BaileysStartupService extends ChannelStartupService {
         `INSERT INTO Chat (id, instanceId, remoteJid, labels, createdAt, updatedAt)
          VALUES (?, ?, ?, JSON_ARRAY(?), NOW(), NOW())
          ON DUPLICATE KEY UPDATE
-           labels = JSON_ARRAY_APPEND(
-             COALESCE(labels, JSON_ARRAY()),
-             '$',
-             ?
+           labels = IF(
+             JSON_CONTAINS(COALESCE(labels, JSON_ARRAY()), JSON_QUOTE(?)),
+             labels,
+             JSON_ARRAY_APPEND(COALESCE(labels, JSON_ARRAY()), '$', ?)
            ),
            updatedAt = NOW()`,
         id,
@@ -5340,6 +5341,7 @@ export class BaileysStartupService extends ChannelStartupService {
         chatId,
         labelId,
         labelId,
+        labelId,
       );
     } else {
       // PostgreSQL version
@@ -5375,18 +5377,17 @@ export class BaileysStartupService extends ChannelStartupService {
         `INSERT INTO Chat (id, instanceId, remoteJid, labels, createdAt, updatedAt)
          VALUES (?, ?, ?, JSON_ARRAY(), NOW(), NOW())
          ON DUPLICATE KEY UPDATE
-           labels = COALESCE(
-             JSON_REMOVE(
-               labels,
-               JSON_UNQUOTE(JSON_SEARCH(labels, 'one', ?))
-             ),
-             JSON_ARRAY()
+           labels = IF(
+             JSON_CONTAINS(COALESCE(labels, JSON_ARRAY()), JSON_QUOTE(?)),
+             JSON_REMOVE(labels, JSON_UNQUOTE(JSON_SEARCH(labels, 'one', ?, '!'))),
+             COALESCE(labels, JSON_ARRAY())
            ),
            updatedAt = NOW()`,
         id,
         instanceId,
         chatId,
         labelId,
+        labelId.replace(/[!%_]/g, '!$&'),
       );
     } else {
       // PostgreSQL version
@@ -5622,13 +5623,15 @@ export class BaileysStartupService extends ChannelStartupService {
         messageType: query?.where?.messageType,
         ...timestampFilter,
         AND: [
-          keyFilters?.id ? { key: { path: ['id'], equals: keyFilters?.id } } : {},
-          keyFilters?.fromMe ? { key: { path: ['fromMe'], equals: keyFilters?.fromMe } } : {},
-          keyFilters?.participant ? { key: { path: ['participant'], equals: keyFilters?.participant } } : {},
+          keyFilters?.id ? { key: { path: jsonPath('id'), equals: keyFilters?.id } } : {},
+          keyFilters?.fromMe ? { key: { path: jsonPath('fromMe'), equals: keyFilters?.fromMe } } : {},
+          keyFilters?.participant ? { key: { path: jsonPath('participant'), equals: keyFilters?.participant } } : {},
           {
             OR: [
-              keyFilters?.remoteJid ? { key: { path: ['remoteJid'], equals: keyFilters?.remoteJid } } : {},
-              keyFilters?.remoteJidAlt ? { key: { path: ['remoteJidAlt'], equals: keyFilters?.remoteJidAlt } } : {},
+              keyFilters?.remoteJid ? { key: { path: jsonPath('remoteJid'), equals: keyFilters?.remoteJid } } : {},
+              keyFilters?.remoteJidAlt
+                ? { key: { path: jsonPath('remoteJidAlt'), equals: keyFilters?.remoteJidAlt } }
+                : {},
             ],
           },
         ],
@@ -5651,13 +5654,15 @@ export class BaileysStartupService extends ChannelStartupService {
         messageType: query?.where?.messageType,
         ...timestampFilter,
         AND: [
-          keyFilters?.id ? { key: { path: ['id'], equals: keyFilters?.id } } : {},
-          keyFilters?.fromMe ? { key: { path: ['fromMe'], equals: keyFilters?.fromMe } } : {},
-          keyFilters?.participant ? { key: { path: ['participant'], equals: keyFilters?.participant } } : {},
+          keyFilters?.id ? { key: { path: jsonPath('id'), equals: keyFilters?.id } } : {},
+          keyFilters?.fromMe ? { key: { path: jsonPath('fromMe'), equals: keyFilters?.fromMe } } : {},
+          keyFilters?.participant ? { key: { path: jsonPath('participant'), equals: keyFilters?.participant } } : {},
           {
             OR: [
-              keyFilters?.remoteJid ? { key: { path: ['remoteJid'], equals: keyFilters?.remoteJid } } : {},
-              keyFilters?.remoteJidAlt ? { key: { path: ['remoteJidAlt'], equals: keyFilters?.remoteJidAlt } } : {},
+              keyFilters?.remoteJid ? { key: { path: jsonPath('remoteJid'), equals: keyFilters?.remoteJid } } : {},
+              keyFilters?.remoteJidAlt
+                ? { key: { path: jsonPath('remoteJidAlt'), equals: keyFilters?.remoteJidAlt } }
+                : {},
             ],
           },
         ],
@@ -5963,7 +5968,7 @@ export class BaileysStartupService extends ChannelStartupService {
     const messages = await this.prismaRepository.message.findMany({
       where: {
         instanceId: this.instanceId,
-        AND: [{ key: { path: ['remoteJid'], not: null } }],
+        AND: [{ key: { path: jsonPath('remoteJid'), not: null } }],
       },
       orderBy: { messageTimestamp: 'desc' },
       select: {
diff --git a/src/api/integrations/chatbot/chatwoot/services/chatwoot.service.ts b/src/api/integrations/chatbot/chatwoot/services/chatwoot.service.ts
index c7a9753aa6..9ee105d9b5 100644
--- a/src/api/integrations/chatbot/chatwoot/services/chatwoot.service.ts
+++ b/src/api/integrations/chatbot/chatwoot/services/chatwoot.service.ts
@@ -21,6 +21,7 @@ import ChatwootClient, {
 import { request as chatwootRequest } from '@figuro/chatwoot-sdk/dist/core/request';
 import { Chatwoot as ChatwootModel, Contact as ContactModel, Message as MessageModel } from '@prisma/client';
 import i18next from '@utils/i18n';
+import { jsonPath } from '@utils/jsonPath';
 import { sendTelemetry } from '@utils/sendTelemetry';
 import axios from 'axios';
 import { WAMessageContent, WAMessageKey } from 'baileys';
@@ -1593,7 +1594,7 @@ export class ChatwootService {
           const lastMessage = await this.prismaRepository.message.findFirst({
             where: {
               key: {
-                path: ['fromMe'],
+                path: jsonPath('fromMe'),
                 equals: false,
               },
               instanceId: instance.instanceId,
@@ -1623,7 +1624,7 @@ export class ChatwootService {
               where: {
                 instanceId: instance.instanceId,
                 key: {
-                  path: ['id'],
+                  path: jsonPath('id'),
                   equals: key.id,
                 },
               },
@@ -2212,7 +2213,7 @@ export class ChatwootService {
           quotedMsg = await this.prismaRepository.message.findFirst({
             where: {
               key: {
-                path: ['id'],
+                path: jsonPath('id'),
                 equals: quotedId,
               },
               chatwootMessageId: {
@@ -2524,7 +2525,7 @@ export class ChatwootService {
             await this.prismaRepository.message.deleteMany({
               where: {
                 key: {
-                  path: ['id'],
+                  path: jsonPath('id'),
                   equals: body.key.id,
                 },
                 instanceId: instance.instanceId,
@@ -2942,7 +2943,7 @@ export class ChatwootService {
         where: {
           Instance: { name: instance.instanceName },
           messageTimestamp: { gte: Number(dayjs().subtract(6, 'hours').unix()) },
-          AND: ids.map((id) => ({ key: { path: ['id'], not: id } })),
+          AND: ids.map((id) => ({ key: { path: jsonPath('id'), not: id } })),
         },
       });
 
diff --git a/src/api/services/channel.service.ts b/src/api/services/channel.service.ts
index 3ba03d5a02..e316056f2f 100644
--- a/src/api/services/channel.service.ts
+++ b/src/api/services/channel.service.ts
@@ -14,6 +14,7 @@ import { Logger } from '@config/logger.config';
 import { NotFoundException } from '@exceptions';
 import { Contact, Message, Prisma } from '@prisma/client';
 import { createJid } from '@utils/createJid';
+import { jsonPath } from '@utils/jsonPath';
 import { WASocket } from 'baileys';
 import { isArray } from 'class-validator';
 import EventEmitter2 from 'eventemitter2';
@@ -623,10 +624,10 @@ export class ChannelStartupService {
         messageType: query?.where?.messageType,
         ...timestampFilter,
         AND: [
-          keyFilters?.id ? { key: { path: ['id'], equals: keyFilters?.id } } : {},
-          keyFilters?.fromMe ? { key: { path: ['fromMe'], equals: keyFilters?.fromMe } } : {},
-          keyFilters?.remoteJid ? { key: { path: ['remoteJid'], equals: keyFilters?.remoteJid } } : {},
-          keyFilters?.participants ? { key: { path: ['participants'], equals: keyFilters?.participants } } : {},
+          keyFilters?.id ? { key: { path: jsonPath('id'), equals: keyFilters?.id } } : {},
+          keyFilters?.fromMe ? { key: { path: jsonPath('fromMe'), equals: keyFilters?.fromMe } } : {},
+          keyFilters?.remoteJid ? { key: { path: jsonPath('remoteJid'), equals: keyFilters?.remoteJid } } : {},
+          keyFilters?.participants ? { key: { path: jsonPath('participants'), equals: keyFilters?.participants } } : {},
         ],
       },
     });
@@ -647,10 +648,10 @@ export class ChannelStartupService {
         messageType: query?.where?.messageType,
         ...timestampFilter,
         AND: [
-          keyFilters?.id ? { key: { path: ['id'], equals: keyFilters?.id } } : {},
-          keyFilters?.fromMe ? { key: { path: ['fromMe'], equals: keyFilters?.fromMe } } : {},
-          keyFilters?.remoteJid ? { key: { path: ['remoteJid'], equals: keyFilters?.remoteJid } } : {},
-          keyFilters?.participants ? { key: { path: ['participants'], equals: keyFilters?.participants } } : {},
+          keyFilters?.id ? { key: { path: jsonPath('id'), equals: keyFilters?.id } } : {},
+          keyFilters?.fromMe ? { key: { path: jsonPath('fromMe'), equals: keyFilters?.fromMe } } : {},
+          keyFilters?.remoteJid ? { key: { path: jsonPath('remoteJid'), equals: keyFilters?.remoteJid } } : {},
+          keyFilters?.participants ? { key: { path: jsonPath('participants'), equals: keyFilters?.participants } } : {},
         ],
       },
       orderBy: {
diff --git a/src/utils/jsonPath.ts b/src/utils/jsonPath.ts
new file mode 100644
index 0000000000..1559051ee3
--- /dev/null
+++ b/src/utils/jsonPath.ts
@@ -0,0 +1,8 @@
+import { configService, Database } from '@config/env.config';
+
+/**
+ * Prisma takes the path of a JSON field filter as an array on PostgreSQL (`['id']`)
+ * but as a JSONPath string on MySQL (`'$.id'`).
+ */
+export const jsonPath = (field: string): any =>
+  configService.get<Database>('DATABASE').PROVIDER === 'mysql' ? `$.${field}` : [field];