diff --git a/CHANGES.md b/CHANGES.md
index f4f61db5d4..d26bc7a86f 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,12 @@
+Synapse 1.6.0rc2 (2019-11-25)
+=============================
+
+Bugfixes
+--------
+
+- Fix a bug which could cause the background database update hander for event labels to get stuck in a loop raising exceptions. ([\#6407](https://github.com/matrix-org/synapse/issues/6407))
+
+
 Synapse 1.6.0rc1 (2019-11-20)
 =============================
 
diff --git a/synapse/__init__.py b/synapse/__init__.py
index 1d962f5dc8..051c83774e 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -36,7 +36,7 @@ try:
 except ImportError:
     pass
 
-__version__ = "1.6.0rc1"
+__version__ = "1.6.0rc2"
 
 if bool(os.environ.get("SYNAPSE_TEST_PATCH_LOG_CONTEXTS", False)):
     # We import here so that we don't have to install a bunch of deps when
diff --git a/synapse/storage/data_stores/main/events_bg_updates.py b/synapse/storage/data_stores/main/events_bg_updates.py
index 0ed59ef48e..aa87f9abc5 100644
--- a/synapse/storage/data_stores/main/events_bg_updates.py
+++ b/synapse/storage/data_stores/main/events_bg_updates.py
@@ -530,24 +530,31 @@ class EventsBackgroundUpdatesStore(BackgroundUpdateStore):
             nbrows = 0
             last_row_event_id = ""
             for (event_id, event_json_raw) in results:
-                event_json = json.loads(event_json_raw)
+                try:
+                    event_json = json.loads(event_json_raw)
 
-                self._simple_insert_many_txn(
-                    txn=txn,
-                    table="event_labels",
-                    values=[
-                        {
-                            "event_id": event_id,
-                            "label": label,
-                            "room_id": event_json["room_id"],
-                            "topological_ordering": event_json["depth"],
-                        }
-                        for label in event_json["content"].get(
-                            EventContentFields.LABELS, []
-                        )
-                        if isinstance(label, str)
-                    ],
-                )
+                    self._simple_insert_many_txn(
+                        txn=txn,
+                        table="event_labels",
+                        values=[
+                            {
+                                "event_id": event_id,
+                                "label": label,
+                                "room_id": event_json["room_id"],
+                                "topological_ordering": event_json["depth"],
+                            }
+                            for label in event_json["content"].get(
+                                EventContentFields.LABELS, []
+                            )
+                            if isinstance(label, str)
+                        ],
+                    )
+                except Exception as e:
+                    logger.warning(
+                        "Unable to load event %s (no labels will be imported): %s",
+                        event_id,
+                        e,
+                    )
 
                 nbrows += 1
                 last_row_event_id = event_id