last winter we stored our PC in the Dallas Texas area for a couple of months while we traveled overseas. When we returned we had the same moisture problem as you describe. I called the manufacturer, name isn’t handy, and they indicated there was no fix.
Sometime over the next couple of months while we traveled it cleared up and has been fine ever since.
When we returned home I did reseal all the housing seams in the hope that it might prevent future problems.
Hope you have similar results.