Interesting thread. Running a Model X from 2017. Chip in on my observations.
I've had a TON of issues with my car, especially centered around the MCU. First of it was like "Clear nav history, clear trip counter type of fixes, which eventually ended up not being a permanent fix obviously.
I then had the MCU replaced, which was promising for a few months, but eventually ending up with the same symptoms, just less frequent. I am now back to square one and still with these symptoms...
Just delivered my car again, today. They now have all the days they need to try and come with a permanent fix of explanation or it because a question of wether or not they have fullfilled their part of the agreement with this car. Luckily I got an MCU replacement, which indicates there is an issue and not just me being pedantic.
Some personal observations are, which are relayed to Tesla Service.
1: I have a tendency to have more issues during winter. (Cold and wet here in Denmark). Statistically my car spend more time at Tesla Service during winter months than summer.
2: I have a tendency to have more issues during wet weather driving. When its raining, my car will go bananas. Periodically, anywhere, randomly in the interface (1-6 seconds). (Laggy music, laggy navigation, laggy main menu, laggy volume adjustment, laggy temperatur controls and so on.)
The older Tesla versions were not assembled with much focus on water tight/moist resistance. So I am guessing, it might be moist/water issue causing some sensors/cabling etc to do some sort of signal flooding/log flooding. Which eventually saturates the overall system, causing random lag and thereby loss of service. This is a speculation, but at this time I would believe if someone said it was a family of gnomes having a cable party every second full moon, explicitly in my car....
Oh yeah, they have all the time claimed that it is only for my car and not a general issue. (Which is good in terms of warranty)