If the volume knob was connected to the amp you’d hear the static from a shitty potentiometer that’s wearing out. Instead what you get is a volume knob that occasionally skips steps because it’s an electromechanical rotary encoder and doesn’t rely on brushes rubbing against a gradient resistive wheel (that literally wears itself away over time which is why car manufacturers switched to rotary encoders in the first place).

The software sucks too (absolutely!) but it’s pretty obvious when the problem is one of the following:

• Skipped control (e.g. volume) steps. Indicates that a contact has worn out (oxidized too much).
• The car suddenly thinks a knob is being turned constantly in one direction (e.g. volume suddenly goes up up up or down down down sometimes forever until you move the knob). This can be “bouncing” or just a contact that’s getting stuck (because dust/car gunk got in there).

These two things are clear indicators of electromechanical components failing. Not normally caused by buggy software.

Neither of these things happen when you use hall effect switches or hall effect rotary encoders (for knobs).