Was getting similar problems using openvix 5.0.031 and my quad sat tuner, no picture breakup , but definitely audio breakup.
Updated to 5.0.032 That added crashing everytime i pressed the menu button.
Firmware version: OpenViX 5.0.028 (2017-10-03)
Kernel / Drivers: 4.4.8 / 20170424
and all audio glitches etc have disappeared again.
Not sure what is causing
1. the audio glitching on numerous channels using latest version
2. pressing the menu button should cause crashes.
As both problems are not in .028 i assume it is an update causing the problems.