were temperatures different? humidity drastically different?

i'm just guessing, but maybe your door lock mechanism is failing. but that's just a guess. it could be electrical as well. the dealer might be able to find something in the diagnostics but maybe not.

you could just leave it and hope for the best or start replacing things. i replaced my door lock mechanism myself. it cost about US$150 and it took me a couple of hours, maybe 3.