After discussions on the pipewire board we found this problem is related to light-locker (part of lightdm?) changing audio device permissions/ownership when the screen is locked.
I have changed to xscreensaver to avoid this problem and everything runs normally. I will report to the package maintainer of light-locker to see if this config issue can be resolved. I am part of the audio group and would expect a logged in session should continue with access even if the screen is locked. You can close this bug now. Thanks/Sorry! Here is the discussion on pipewire: https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/5002
