No insult... and Welcome Back! 
In the future, please try to keep the emotions out when you post. They don't help solve the problem.
From your facts, and those of others reporting on the volume level dropping, we FINALLY identified the problem!
If you click Stop (or Ctrl+Spacebar) while a song is fading out, but before the fade is done, several things combined to create the "random" dropping volume level:
1. Say your Fade Out setting is 5, and you stop play after 3 seconds of fade. The "song end" will happen in 2 seconds.
2. However, the fade out on the Stop operation is the same as the Playlist, which for my example is 5 seconds.
3. Thus, only 2 seconds remain until the song "file" ends playing, but the Stop fade continues playing the fade for 5 seconds. Not good!
4. The Windows volume slider (whichever it is
) was dropping down as the original fade happened, but when stopped it faded no further.
5. When the file end was reached, there was an undefined pseudo-crash that did not reset the volume slider back to its initial setting.
6. Thus, the volume slider was left somewhat lower than when started. This also "appeared" to be a random amount, based on how fast you clicked the Stop button once the song Fade Out started; the faster you clicked, the less the volume drop happened for "that song", which is why some users reported 45 minutes before the volume was 0%.
We identified this sequence and the code fix may be done by tomorrow AM.
We would have never identified this "multi-step randomized mess" without everyone's
factual feedback.
Great Job by EVERYONE!