My brother bought sme maple blanks that were coated with wax. He labeled them and put them on a shelf 3 weeks later they they were black with mold between the wax and blanks. Is that common and are they still safe to turn.
Don't turn them without appropriate safety equipment: masking, filtration, etc.
You don't want that in your lungs.
IIWM, I would turn to minimal round—the least amount you can remove to get rid of the mold.
Then nuke 'em until dry.
Then, let them sit a while and see if they stay mold free.
I would not mess with these in my shop. I would not want any of that mold in my dust collection or shop vac. I would not want to sand the mold off an turn it into small particulate.
Sorry, I know this is harsh, but wood can be replaced, your health cannot.
I would consider cutting off the molded portions outside wearing a mask.
I ordered a bunch of wood from a seller in Indonesia. It all showed up with mold all over it. I sealed int in plastic bags and threw it all away. Heartbreaking but I wasn't willing to risk my health. I was able to get the vendor to replace it.