I continue to get this same message when driving in the rain... Typically clears itself (dries out?) within 48hrs. Fortunately, it hasn't yet reduced power. YMMV
I currently have the doors off, front roof panels off and the rear glass up:
I don't yet have a hoist/lift system so top-off is a bit more effort solo. But when it's off, I've traveled 100's of miles with just the two front panels: