What worked for me ultimately is reformat all of my microSD cards to Fat32. (Reinitializing the camera without formatting the cards didn’t work.) Had issues formatting anything larger than 32GB to Fat32 though without installing a free software to do that. That said, once I took the card out from one v3 camera to another v3 camera, I had to format it again before the new camera would recognize the card.
I did have to reinitialize the last camera that I put a Fat32 formatted card in for it to recognize the microSD card. So seems like need to do both for it to work.