Audio Issues When In-place Upgrading to Leap 15.6

Hi Folks, I'm encountering audio issues after in-place upgrades from Leap 15.5 to 15.6. Out of three upgrades so far, I lost sound on a HP laptop and a Dell desktop. An MSI desktop is working okay.  I have to admit I haven't had sound issues with openSUSE for decades, or so it seems, and I'm rusty a diagnosing what's going on. I vaguely recall a thread here about pulseaudio issues, could this be related? If I'm seeing this on two out of three upgrades this must be a common problem. Any suggestions would be appreciated. Regards, Lew