Firefox pauses when switching users

it used to not do this, but lately i can no longer use Firefox to play music i find on any website such as YouTube. but mplayer still works fine playing music i already have as files (regardless of format). i have a user named "music" that owns my music file collection and database of URLs that have music i like (the majority are on YouTube. i login to "music", start playing what i want to hear, then switch to the user i want to do things with. i am currently playing some of my Nordic music on user "music" as i enter this post on user "forums". when i switch with Firefox, it plays for about 20 to 30 seconds then freezes. when i switch back to user "music" it resumes where it froze.

i am running Xubuntu 18.04.6 last upgraded this past weekend
Firefox is 92.0 but the problem started many versions back
Lightdm is 1.26.0
Linux is 5.4.0
Pulseaudio is 1:11.1 and running in system mode
Xfce is 4.12.1

anyone know what is going on?