Roger that, Roger, on the moisture condensing. Under prev. owner, my
house had a variety of air leaks from heated space into attic. Roofing
nails, having their large heads very near the Great Outdoors and having
much greater thermal conductivity than plywood deck, served as main
points of condensation. Such that you could see pattern of staining
around their protruding shanks in summer. Slowly fading now. And ...
energy consumption waaaaay down.

OP might look for entry point(s) of relatively high absolute humidity
air from below. They sure are there, and with chimney-effect it doesn't
take a lot of flow-area.

HTH,
J