While chalkbrood can be made worse with wet weather, if it persists, then you need a new queen, it is often a queen issue. So if it is a strong hive, I'd plan on requeening asap in the spring. I had a similar situation, CB during the summer, next spring I requeened and it cleared up.
As far as the mold...there's moldable material that gets on the boxes (propolis, wax, honey) and that will mold. Not a big deal. That super, while it may not be new, doesn't show sign of a lot of use, so the bees probably haven't been in there polishing and propolizing and doing what they do when they are crowded up in there, so it gets a little moisture but not a good bee-cleaning.
Mold doesn't cause chalkbrood, although chalkbrood is a type of fungus. Both can be made worse by moisture, but both are controlled by strong hives, good queens.