First I've heard of that, Kyle! I have a 2D & 3D, and they live on a covered porch. I do have rubber plugs in the meat probe port, to keep bugs and moisture out. The bottom of the controller is solid steel, so the only way there could be moisture in the controller is if the seal is not intact or you've gotten water in the meat port.
The easiest way to fix this is remove the controller screws, and dry it out! Not sure how it got moisture inside, and like I've said, I've never heard of this. Unscrew the controller, and take a hair dryer to it to thoroughly dry it out, check the gasket and reinstall.