Installed 2.1.52 last night. It certainly did some robust things:
1. For the first time in months, CarPlay did not load. It wasn't even possible to delete and reinstall the phone to do this, as the fone didn't show.
2. On the highway, the motors died. Everything else (except car play) was working, but the car lost all motive energy on US 101 in Palo Alto.
3. After trying a reset, (walking away and waiting 15 minutes). The car ran again, carplay did not, and the app now shows the software rolled back to 2.1.50.
Robust that!
(yes, I robustly called service.)