fix: Ensure to publish on the correct transport

src/state/CallViewModel/CallViewModel.ts

@@ -120,6 +120,7 @@ import {
   type LocalMatrixLivekitMember,
   type RemoteMatrixLivekitMember,
   type MatrixLivekitMember,
+  areLivekitTransportsEqual,
 } from "./remoteMembers/MatrixLivekitMembers.ts";
 import {
   type AutoLeaveReason,
@@ -517,6 +518,26 @@ export function createCallViewModel$(
     ),
   );
 
+  // Observe the transport we should publish
+  const publishingTransport$ = localTransport$.pipe(
+    // observe the active$ transport
+    switchMap((t) => {
+      return combineLatest([t.active$, t.advertised$]).pipe(
+        map(([active, advertised]) => {
+          if (active?.transport) {
+            // use the active one (oldest member transport)
+            return active.transport;
+          } else {
+            // There is no active transport, we might just be the first member in the call
+            // so use the advertised to start
+            return advertised;
+          }
+        }),
+      );
+    }),
+    distinctUntilChanged(areLivekitTransportsEqual),
+  );
+
   const localMembership = createLocalMembership$({
     scope,
     homeserverConnected: createHomeserverConnected$(
@@ -546,9 +567,7 @@ export function createCallViewModel$(
     },
     connectionManager,
     matrixRTCSession,
-    localTransport$: scope.behavior(
-      localTransport$.pipe(switchMap((t) => t.advertised$)),
-    ),
+    localTransport$: scope.behavior(publishingTransport$),
     logger: logger.getChild(`[${Date.now()}]`),
   });