When I monitor audio in PPro Beta (25.3.0 Build 37), it's much quieter than in the release version (25.2.0 Build 147). I'm not talking about audio track levels or anything like that; here's the situation:
Load up PPro Beta
Create a new project
Drag in a WAV file (it's a stock music file I downloaded from audiio.com today)
Double-click it to play it. It peaks just below 0dB in PPro's audio meter, as you'd expect.
Realise it's not very loud, even with my system volume turned up to 100 (it's quite loud, but not VERY loud as you'd expect)
Save the project.
Load up PPro Release
Load up that same project.
Play the audio file; it peaks just below 0dB in PPro's audio meter, as you'd expect.
Realise it sounds MUCH louder than in PPro beta - even though the actual loudness of the track has not changed.
Rummage through the audio hardware prefs of both apps, and see that in PPro Beta, I have this:

...but in PPro Release, I have this:

The output mapping is very different, even though it's the same project. I assume it's because PPro Beta is trying to route some of the audio to non-existent outputs (I'm monitoring it using Beyerdynamic DT700 Pro headphones in my PC's bog-standard headphone jack). None of those output mappings seem to be editable.
None of this affects the actual editing or exporting of media - the actual levels are all fine and consistent between both apps - it's just the monitoring of the audio that is the issue here (in fact if I play back something in VLC player that I've just exported from PPro Beta, I have to remember to turn my PC's volume down considerably in case I blow my eardrums apart!)
Any thoughts on why this might be happening? I'm on Windows 10.