CAN devices I have limited experience with, but I know at least in the automotive industry, vehicles often have various CAN devices that have various sleep states. Like, shut car off, it holds brake system for a few minutes and then unlocks the brakes and that ECU shuts down. Later on, an emissions ECU may run a self-diagnostic. After a few days being powered off, the security ECU goes into low power and turns off wireless doorlocks. After the voltage drops too low, the ECU in the head unit ostensibly shuts down, and the next time the car is started, the head unit has to do a cold-reboot and takes a fortnight.

Could be one of those CAN devices takes some time to get into the "off-adjacent" state to manifest the bug?

[–] [email protected] 1 points 6 hours ago

Largely for safety reasons, anytime the system is turned off power is instantly cut to the entire system. All of our CAN devices boot up much faster than the Pi does. Once the Pi boots, it sets up CAN communication.