Mine all have exFAT 128G cards in them no issues. I did have a Panv3 pretty much completely die, it was upside down under an eave and the rain and wind one day got inside. I was able to bring it back to life by leaving it in a bag of rice for a couple of days, but YMMV on that.
There are methods to attempt to clean the SD card slot too in case it just got some dirt inside it or something but they are hit or miss. Your symptoms sound like intermittent/incomplete reading or contact of the card, probably something to do with the slot or controller.