Normal on anything that has to work outside. Also, hardly an impediment to repair. I've done it myself on a car ECU: open case, scrape off conformal coating, desolder blown IGBT, replace with IGBT salvaged from junkyard unit, spray on new conformal coating, done - been working like that now for 5 years.
Parts pairing is also a/the reason you can't just swap in the junkyard unit even though it came from a car with the same engine. We tried it - did not work.
Potting within a brick of epoxy is the real dick move, but also not impossible to repair either.
That pairing is for theft reasons - chop shops will steal a car, take the parts off and sell them. However the expensive computers are paired and so they won't work when sold this way thus making the value of a car to a shop shop much less and so helping prevent that theft mode.
Though I think there should be a process to get the parts paired after verifying the car isn't stolen. I'm not sure what that would be though.
Parts pairing is also a/the reason you can't just swap in the junkyard unit even though it came from a car with the same engine. We tried it - did not work.
Potting within a brick of epoxy is the real dick move, but also not impossible to repair either.