It's because they cheaped out and used (cheap) electromechanical switches for the buttons and electromechanical rotary encoders for the knobs.
If they used magnetic hall effect switches they'd never glitch (unless the microcontroller itself is glitching). Hall effect switches are forever.
(And no: Even cars in Arizona don't get hot enough to wreck rare earth magnets... They'll lose strength slightly above 80°C but not enough to matter since the car knows its internal temp and can compensate if they didn't get the better sensors that auto-compensate).
For reference, hall effect switches and encoders aren't really that much more expensive for something like a car where you're going to be using/making millions of them. It probably saves pennies per car to use the cheap switches.