Does this situation(CAN_H short to GND) could be reproduced through vibration?
Manually short the pins is an unexpected action to us, or you could short any pins and destroy the board…
We’ve seen other real use case like suspend/resume to check if it would be alive and have the similar behavior as yours(No buffer space available.). It should be fixed in the next release(JP5.1.2), but I’m not sure if it is the exactly same issue.