j5, please contact your Schoeps dealer or (assuming that you're in the U.S.) the representative Redding Audio. What you describe is extremely weird, and should not be occurring. I say this as someone who owns 23 Schoeps capsules and having recorded 2000+ live concert performances with them over more than 30 years; I take no special precautions against moisture but have never had any experience like what you've described.
I also used to record live outdoor sound effects for hours at a time including Walden Pond and other sites on or close to water, using Schoeps MK 4 or MK 5 capsules; I never had any problems whatsoever. If you were in a steamy jungle with moisture condensing outright, I could understand it, but if you're working in a temperate climate and more or less normal conditions of humidity, as many film and video sound people do all the time with Schoeps microphones (including a lot of outdoor work), I suspect there may be a defect in the internal insulation of one of your capsules, and if so, it should be repaired.
This is not just some unfortunate but typical behavior for this kind of microphone; it is extremely anomalous behavior, and should be looked into.
--best regards