diff --git a/syncapi/consumers/sendtodevice.go b/syncapi/consumers/sendtodevice.go
index 1735db917..c0b432256 100644
--- a/syncapi/consumers/sendtodevice.go
+++ b/syncapi/consumers/sendtodevice.go
@@ -115,7 +115,7 @@ func (s *OutputSendToDeviceEventConsumer) onMessage(ctx context.Context, msgs []
 		_, senderDomain, _ := gomatrixserverlib.SplitID('@', output.Sender)
 		if requestingDeviceID != "" && senderDomain != s.serverName {
 			// Mark the requesting device as stale, if we don't know about it.
-			if err := s.keyAPI.PerformMarkAsStaleIfNeeded(ctx, &keyapi.PerformMarkAsStaleRequest{
+			if err = s.keyAPI.PerformMarkAsStaleIfNeeded(ctx, &keyapi.PerformMarkAsStaleRequest{
 				UserID: output.Sender, Domain: senderDomain, DeviceID: requestingDeviceID,
 			}, &struct{}{}); err != nil {
 				logger.WithError(err).Errorf("failed to mark as stale if needed")
diff --git a/syncapi/internal/keychange_test.go b/syncapi/internal/keychange_test.go
index 80d2811be..3b9c8221c 100644
--- a/syncapi/internal/keychange_test.go
+++ b/syncapi/internal/keychange_test.go
@@ -22,6 +22,10 @@ var (
 
 type mockKeyAPI struct{}
 
+func (k *mockKeyAPI) PerformMarkAsStaleIfNeeded(ctx context.Context, req *keyapi.PerformMarkAsStaleRequest, res *struct{}) error {
+	return nil
+}
+
 func (k *mockKeyAPI) PerformUploadKeys(ctx context.Context, req *keyapi.PerformUploadKeysRequest, res *keyapi.PerformUploadKeysResponse) error {
 	return nil
 }