Bug report:
https://bugzilla.kernel.org/enter_bug.cgi?product=Drivers
You have to provide pulseaudio verbose log, output of alsa-info.sh , lsusb -vvvv and step to reproduce your problem when you report the bug
==> /var/log/user.log <==
May 25 06:38:06 atom pulseaudio[6754]: [alsa-sink-USB Audio] alsa-sink.c: ALSA woke us up to write new data to the device, but there was actually nothing to write!
May 25 06:38:06 atom pulseaudio[6754]: [alsa-sink-USB Audio] alsa-sink.c: Most likely this is a bug in the ALSA driver '(null)'. Please report this issue to the ALSA developers.
Name of alsa sink seem changed from USB-audio to null, did you find any unplug event if USB audio device in system log
Any error message related to USB controllers and your audio card
May 25 06:38:06 atom pulseaudio[6754]: [alsa-sink-USB Audio] alsa-sink.c:
We
were woken up with POLLOUT set -- however a subsequent snd_pcm_avail() returned 0 or another value < min_avail.