The mold wouldn't concern me, but the amount of bees would. Can't tell much from the picture, but it looks like three empty frames on that side of the box. If the other side of the box is about the same, that means you have four frames of bees in a ten frame box. I don't know if you have hive beetles, but down here that box would be slimed in two weeks.
If it were mine, I'd move them to a nuc until they completely covered all five frames before putting them back in a ten frame box.