One thing that I think I see in there is that I'm the error message asks you to "or use SharedTransitionLayout instead" and you are already doing that.
If anything, you get an error which doesn't give you a path to move forward since it gives you the wrong advice. That by itself is worth a bug report.
From a glance at all the code it looks like you're doing stuff alright.
The one last thing I'd try if you really don't want to file a bug report yet is remove all the Scaffolds from in there, I see at least a couple of them. To remove the chance it's a problem with sub composition acting weird. That's what I'd do at least