diff --git a/src/github.com/matrix-org/dendrite/syncapi/storage/current_room_state_table.go b/src/github.com/matrix-org/dendrite/syncapi/storage/current_room_state_table.go
index 0990f429b..4dd440a66 100644
--- a/src/github.com/matrix-org/dendrite/syncapi/storage/current_room_state_table.go
+++ b/src/github.com/matrix-org/dendrite/syncapi/storage/current_room_state_table.go
@@ -217,9 +217,11 @@ func (s *currentRoomStateStatements) upsertRoomState(
 	ctx context.Context, txn *sql.Tx,
 	event gomatrixserverlib.Event, membership *string, addedAt int64,
 ) error {
+	var containsURL bool
 	var content map[string]interface{}
-	json.Unmarshal(event.Content(), content)
-	_, containsURL := content["url"]
+	if json.Unmarshal(event.Content(), &content) != nil {
+		_, containsURL = content["url"]
+	}
 
 	stmt := common.TxStmt(txn, s.upsertRoomStateStmt)
 	_, err := stmt.ExecContext(
diff --git a/src/github.com/matrix-org/dendrite/syncapi/storage/invites_table.go b/src/github.com/matrix-org/dendrite/syncapi/storage/invites_table.go
index 37a361837..1a214b791 100644
--- a/src/github.com/matrix-org/dendrite/syncapi/storage/invites_table.go
+++ b/src/github.com/matrix-org/dendrite/syncapi/storage/invites_table.go
@@ -85,9 +85,11 @@ func (s *inviteEventsStatements) prepare(db *sql.DB) (err error) {
 func (s *inviteEventsStatements) insertInviteEvent(
 	ctx context.Context, inviteEvent gomatrixserverlib.Event,
 ) (streamPos int64, err error) {
+	var containsURL bool
 	var content map[string]interface{}
-	json.Unmarshal(inviteEvent.Content(), content)
-	_, containsURL := content["url"]
+	if json.Unmarshal(inviteEvent.Content(), &content) != nil {
+		_, containsURL = content["url"]
+	}
 
 	err = s.insertInviteEventStmt.QueryRowContext(
 		ctx,
diff --git a/src/github.com/matrix-org/dendrite/syncapi/storage/output_room_events_table.go b/src/github.com/matrix-org/dendrite/syncapi/storage/output_room_events_table.go
index 0d4525b20..a103d1d39 100644
--- a/src/github.com/matrix-org/dendrite/syncapi/storage/output_room_events_table.go
+++ b/src/github.com/matrix-org/dendrite/syncapi/storage/output_room_events_table.go
@@ -224,9 +224,11 @@ func (s *outputRoomEventsStatements) insertEvent(
 		txnID = &transactionID.TransactionID
 	}
 
+	var containsURL bool
 	var content map[string]interface{}
-	json.Unmarshal(event.Content(), content)
-	_, containsURL := content["url"]
+	if json.Unmarshal(event.Content(), &content) != nil {
+		_, containsURL = content["url"]
+	}
 
 	stmt := common.TxStmt(txn, s.insertEventStmt)
 	err = stmt.QueryRowContext(