Unresponsive volume control

Hello all,
Happy volumio user here, in general the software is excellent. I got one minor, annoying bug to report though: At random times the volume control stops working. When this happens the volume is displayed as zero on the playback screen, yet the music keeps playing on the previous volume setting. Once this happens I need to reboot the Raspberry to regain volume control. Once the device is back up, volume control works fine until the next time it bugs out.

It’s a small but annoying little bug, sometimes requiring several reboots each day. Any tips on how to solve it? Volume control mixer is set to hardware.