[AUDIO] SysAudio stopped working within a session with rather descriptive error message

reactOS 0.4.2RC1

Easy scenario: I had a fresh boot, sound was in working state as

(drivers/wdm/audio/legacy/wdmaud/control.c:161) Closing device 800001F4

in
a-ros0.4.2RC1-soundStoppedWorkingWithinASession.log
proves - this message comes only when start-sound is playing correctly.

I then did only very basic stuff:
-download & test fall 0.1.3 a bit
-downloading & starting Fox Audio Player 0.10.2.

When I tried to play the ros-start-sound file within FAP (which usually succeeds),
I got this pretty descriptive message

(ntoskrnl/io/iomgr/file.c:148) You are seeing this because the following ROS driver: \Driver\SYSAUDIO

 sucks. Please fix it's AddDevice Routine

everytime I tried to play the wav.

After a quick reboot, playing the sound-file worked perfectly:
b-ros0.4.2RC1-afterRebootSameProcedureOK.log

Maybe by comparing both logs in Beyond Compare, a skilled coder can find out, what exactly breaks our sound driver here.
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Please don't tell me that it's often needed to reboot multiple times before sound driver starts working, as this is something different.
Here it stopped working during the session.