diff --git a/federationapi/routing/send.go b/federationapi/routing/send.go
index 35a611ee0..dde07701a 100644
--- a/federationapi/routing/send.go
+++ b/federationapi/routing/send.go
@@ -253,11 +253,8 @@ type txnFederationClient interface {
 
 func (t *txnReq) processTransaction(ctx context.Context) (*gomatrixserverlib.RespSend, *util.JSONResponse) {
 	results := make(map[string]gomatrixserverlib.PDUResult)
-	//var resultsMutex sync.Mutex
-
 	var wg sync.WaitGroup
 	var tasks []*inputTask
-	wg.Add(1) // for processEDUs
 
 	for _, pdu := range t.PDUs {
 		pduCountTotal.WithLabelValues("total").Inc()
@@ -322,16 +319,12 @@ func (t *txnReq) processTransaction(ctx context.Context) (*gomatrixserverlib.Res
 		}
 		tasks = append(tasks, task)
 		worker.input.push(task)
-		if !worker.running.CAS(false, true) {
+		if worker.running.CAS(false, true) {
 			go worker.run()
 		}
 	}
 
-	go func() {
-		defer wg.Done()
-		t.processEDUs(ctx)
-	}()
-
+	t.processEDUs(ctx)
 	wg.Wait()
 
 	for _, task := range tasks {
@@ -703,14 +696,9 @@ func checkAllowedByState(e *gomatrixserverlib.Event, stateEvents []*gomatrixserv
 	return gomatrixserverlib.Allowed(e, &authUsingState)
 }
 
-var processEventWithMissingStateMutexes = internal.NewMutexByRoom()
-
 func (t *txnReq) processEventWithMissingState(
 	ctx context.Context, e *gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion,
 ) error {
-	processEventWithMissingStateMutexes.Lock(e.RoomID())
-	defer processEventWithMissingStateMutexes.Unlock(e.RoomID())
-
 	// We are missing the previous events for this events.
 	// This means that there is a gap in our view of the history of the
 	// room. There two ways that we can handle such a gap: