I did find the Intel graphics driver was not the latest, so I installed that. I also checked JR to make sure I was on v30.0.76. Restarted the computer a couple of times and then:
Start JR - okay
Play Movie A - okay
Play Movie B - okay
Play Movie A - failed
Play Movie B - failed
I enabled/disabled exclusive mode, both in JR and the audio device in windows, no change.
So the problem remains.
But I did go ahead and install the latest Kodi software and tried it. I configured Kodi for Passthrough (bitstreaming) and used the same AVM60(WASAPI) audio device. No problems. I can play any movie, in any order and multiple times and it works every time. The AVM60 reports the audio stream e.g. as DTS-HD-Master so it is definitely bitstreaming.
The problem must be in the WASAPI plugin within JR. I would be happy to help the developers troubleshoot this problem as I prefer to use JR instead of Kodi.