diff --git a/.github/workflows/beeper-ci.yaml b/.github/workflows/beeper-ci.yaml
index 3394e6f67..0fea4245a 100644
--- a/.github/workflows/beeper-ci.yaml
+++ b/.github/workflows/beeper-ci.yaml
@@ -113,6 +113,7 @@ jobs:
             tag=$(cat pyproject.toml | grep -E "^version =" | sed -E 's/^version = "(.+)"$/\1/')
           else
             tag="${{ github.head_ref || github.ref_name }}"
+            tag="${tag//\//-}"
           fi
 
           docker buildx build \
diff --git a/synapse/logging/_terse_json.py b/synapse/logging/_terse_json.py
index f98c72ba2..ec59e4751 100644
--- a/synapse/logging/_terse_json.py
+++ b/synapse/logging/_terse_json.py
@@ -132,5 +132,7 @@ def format(self, record: logging.LogRecord) -> str:
             "level": record.levelname.lower(),
             "time": round(record.created, 2),
         }
+        if record.exc_info and record.exc_info[0]:
+            event["exc_traceback"] = self.formatException(record.exc_info)
 
         return self._format(record, event)