Open apps 'disappear' when starting coherence

The next in the ongoing saga of Parallels post the Windows 1803 update...

1. Start Parallels in Full Screen Mode
2. Run a couple of apps
3. Exit Full Screen
4. Start Coherence
5. Try to find the running instances of the previously started apps - nowhere to be found.

MacOS dock shows they are running but when you try to switch to them nothing happens. If you try to 'show all windows' from the dock they don't appear. If you start a second instance of the same app it works ok, you just can't see/find the original instance. Windows task manager shows they are running but you can't switch to them. You can see them in Activity Monitor.

Switch back out of coherence and they reappear.

Anyone have any ideas on how to fix this?