diff --git a/lib/src/event.dart b/lib/src/event.dart
index 2ccc8e1..6305a1c 100644
--- a/lib/src/event.dart
+++ b/lib/src/event.dart
@@ -319,11 +319,11 @@ class Event extends MatrixEvent {
     if (status != -1) return null;
     // we do not remove the event here. It will automatically be updated
     // in the `sendEvent` method to transition -1 -> 0 -> 1 -> 2
-    final eventID = await room.sendEvent(
+    final newEventId = await room.sendEvent(
       content,
-      txid: txid ?? unsigned['transaction_id'],
+      txid: txid ?? unsigned['transaction_id'] ?? eventId,
     );
-    return eventID;
+    return newEventId;
   }
 
   /// Whether the client is allowed to redact this event.
diff --git a/lib/src/room.dart b/lib/src/room.dart
index 234ad39..8ba80b8 100644
--- a/lib/src/room.dart
+++ b/lib/src/room.dart
@@ -691,7 +691,10 @@ class Room {
                 ..eventId = messageID
                 ..senderId = client.userID
                 ..originServerTs = DateTime.now()
-                ..unsigned = {MessageSendingStatusKey: 0},
+                ..unsigned = {
+                  MessageSendingStatusKey: 0,
+                  'transaction_id': messageID,
+                },
             ]))));
     await client.handleSync(syncUpdate);
 
@@ -709,8 +712,6 @@ class Room {
       );
       syncUpdate.rooms.join.values.first.timeline.events.first
           .unsigned[MessageSendingStatusKey] = 1;
-      syncUpdate.rooms.join.values.first.timeline.events.first
-          .unsigned['transaction_id'] = messageID;
       syncUpdate.rooms.join.values.first.timeline.events.first.eventId = res;
       await client.handleSync(syncUpdate);
       return res;