Communication between 4.3.0 and 4.3.1 fails

I'm using comlink with iframes and I'm seeing communication between frames fails when the parent app is running v4.3.1 and the child app is running 4.3.0.
Specifically the promise returned from this line never seems to resolve:
```ts
// child app
wrap(windowEndpoint(window.parent, window, targetOrigin)).callParentMethod();
```
This is a major issue for us because the two different frames are separate apps maintained by different teams and have different release schedules so it impractical for us to coordinate a comlink upgrade. For now we are pinning our versions to 4.3.0