diff --git a/lib/mongo/client.rb b/lib/mongo/client.rb
index 4fc3250a83..77d9767a99 100644
--- a/lib/mongo/client.rb
+++ b/lib/mongo/client.rb
@@ -625,7 +625,11 @@ def initialize(addresses_or_uri, options = nil)
             build_encrypter
           end
         end
-      rescue StandardError
+      # ScriptError is rescued in addition to StandardError because
+      # Mongo::Crypt::Binding raises a LoadError when libmongocrypt cannot be
+      # found. Without it the cluster built above would be left open, leaking
+      # its monitoring and connection pool threads.
+      rescue StandardError, ScriptError
         begin
           @cluster.close
         rescue StandardError => e
diff --git a/spec/mongo/client_construction_spec.rb b/spec/mongo/client_construction_spec.rb
index fc88be7fcb..582eef5dbe 100644
--- a/spec/mongo/client_construction_spec.rb
+++ b/spec/mongo/client_construction_spec.rb
@@ -393,6 +393,32 @@
         end
       end
 
+      # Mongo::Crypt::Binding raises a LoadError, which is a ScriptError and
+      # not a StandardError, when libmongocrypt is not available. The cluster
+      # is built before the encrypter, so it must be closed before the error
+      # propagates out of the constructor. This context deliberately sits
+      # outside the require_libmongocrypt guard above: the scenario it covers
+      # only happens when libmongocrypt is missing.
+      context 'when building the encrypter raises a LoadError' do
+        before do
+          allow(Mongo::Crypt::AutoEncrypter).to receive(:new).and_raise(LoadError, 'no libmongocrypt')
+        end
+
+        it 'closes the cluster and propagates the error' do
+          expect_any_instance_of(Mongo::Cluster).to receive(:close).and_call_original
+
+          expect do
+            new_local_client_nmio(
+              SpecConfig.instance.addresses,
+              auto_encryption_options: {
+                key_vault_namespace: 'keyvault.datakeys',
+                kms_providers: { local: { key: 'x' * 96 } },
+              }
+            )
+          end.to raise_error(LoadError, /no libmongocrypt/)
+        end
+      end
+
       context 'timeout options' do
         let(:client) do
           new_local_client(
diff --git a/spec/runners/crud/requirement.rb b/spec/runners/crud/requirement.rb
index cb3ee755cb..4099312f38 100644
--- a/spec/runners/crud/requirement.rb
+++ b/spec/runners/crud/requirement.rb
@@ -114,7 +114,11 @@ def satisfied?
           ok &&= !SpecConfig.instance.auth?
         end
         if @csfle
-          ok &&= !!(ENV['LIBMONGOCRYPT_PATH'] || ENV['FLE'])
+          # Evergreen exports FLE="" on variants that do not exercise FLE, and
+          # an empty string is truthy in Ruby. Treat an empty value as
+          # "libmongocrypt is not available", the same way
+          # Mrss::LiteConstraints#require_libmongocrypt does.
+          ok &&= !(ENV['LIBMONGOCRYPT_PATH'] || '').empty? || !(ENV['FLE'] || '').empty?
           if ok && @csfle.is_a?(Hash) && (min_version = @csfle['minLibmongocryptVersion'])
             actual_version = Mongo::Crypt::Binding.mongocrypt_version(nil)
             ok &&= Mongo::Crypt::Binding.parse_version(actual_version) >= Gem::Version.new(min_version)
diff --git a/spec/spec_tests/data/unified/valid-pass/poc-queryable-encryption.yml b/spec/spec_tests/data/unified/valid-pass/poc-queryable-encryption.yml
new file mode 100644
index 0000000000..797904ee95
--- /dev/null
+++ b/spec/spec_tests/data/unified/valid-pass/poc-queryable-encryption.yml
@@ -0,0 +1,86 @@
+description: poc-queryable-encryption
+
+schemaVersion: "1.23"
+
+runOnRequirements:
+  - minServerVersion: "7.0"
+    csfle: true
+    # QE is not supported on standalone servers
+    topologies: [ replicaset, load-balanced, sharded ]
+
+createEntities:
+  - client:
+      id: &client0 client0
+      autoEncryptOpts:
+        keyVaultNamespace: keyvault.datakeys
+        kmsProviders:
+          local:
+            key: Mng0NCt4ZHVUYUJCa1kxNkVyNUR1QURhZ2h2UzR2d2RrZzh0cFBwM3R6NmdWMDFBMUN3YkQ5aXRRMkhGRGdQV09wOGVNYUMxT2k3NjZKelhaQmRCZGJkTXVyZG9uSjFk
+  - database:
+      id: &encryptedDB encryptedDB
+      client: *client0
+      databaseName: &encryptedDBName poc-queryable-encryption
+  - collection:
+      id: &encryptedColl encryptedColl
+      database: *encryptedDB
+      collectionName: &encryptedCollName encrypted
+  - client:
+      id: &client1 client1
+  - database:
+      id: &unencryptedDB unencryptedDB
+      client: *client1
+      databaseName: *encryptedDBName
+  - collection:
+      id: &unencryptedColl unencryptedColl
+      database: *unencryptedDB
+      collectionName: *encryptedCollName
+
+initialData:
+  - databaseName: keyvault
+    collectionName: datakeys
+    documents:
+      - _id: &keyid { $binary: { base64: EjRWeBI0mHYSNBI0VniQEg==, subType: "04" } }
+        keyMaterial: { $binary: { base64: sHe0kz57YW7v8g9VP9sf/+K1ex4JqKc5rf/URX3n3p8XdZ6+15uXPaSayC6adWbNxkFskuMCOifDoTT+rkqMtFkDclOy884RuGGtUysq3X7zkAWYTKi8QAfKkajvVbZl2y23UqgVasdQu3OVBQCrH/xY00nNAs/52e958nVjBuzQkSb1T8pKJAyjZsHJ60+FtnfafDZSTAIBJYn7UWBCwQ==, subType: "00" } }
+        creationDate: { $date: { $numberLong: "1641024000000" } }
+        updateDate: { $date: { $numberLong: "1641024000000" } }
+        status: 1
+        masterKey:
+          provider: local
+  - databaseName: *encryptedDBName
+    collectionName: *encryptedCollName
+    documents: []
+    createOptions:
+      encryptedFields:
+        fields:
+          - keyId: *keyid
+            path: 'encryptedInt'
+            bsonType: 'int'
+            queries: {'queryType': 'equality', 'contention': {'$numberLong': '0'}}
+
+tests:
+  - description: insert, replace, and find with queryable encryption
+    operations:
+      - object: *encryptedColl
+        name: insertOne
+        arguments:
+          document:
+            _id: 1
+            encryptedInt: 11
+      - object: *encryptedColl
+        name: replaceOne
+        arguments:
+          filter: { encryptedInt: 11 }
+          replacement: { encryptedInt: 22 }
+      - object: *encryptedColl
+        name: find
+        arguments:
+          filter: { encryptedInt: 22 }
+        expectResult:
+          - _id: 1
+            encryptedInt: 22
+      - object: *unencryptedColl
+        name: find
+        arguments:
+          filter: {}
+        expectResult:
+          - { _id: 1, encryptedInt: { $$type: binData }, __safeContent__: [ { "$binary" : { "base64" : "rhS16TJojgDDBtbluxBokvcotP1mQTGeYpNt8xd3MJQ=", "subType" : "00" } } ] }
\ No newline at end of file