Hi @yzerman001
Welcome to the Sonos Community!
Sorry to hear of this issue you are having with the volume on your Beam Gen 2 while playing YouTube content.
I have noticed on my own system that after a while of not playing, the YouTube app on my nVidia Shield Pro will be muted and will ramp up the volume in the first few seconds of playing something again. It never used to do this - I’m fairly sure it was with a recent YouTube app update that this started.
It sounds different from what you describe, however - I never hear the volume reduce by itself.
I recommend you get in touch with our technical support team who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports. Please recreate the issue and submit a support diagnostic before calling in.
If your Philips TV has a YouTube app, you might want to try that to see if it is any different.
I hope this helps.
"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein