If you can eliminate the possibility of light leaks, heat stress, etc, then you have a bad natural herm.. if you look at your grow and find problems, the herm trait might not appear in the next goround when you fix the problems.

The best thing to do is just pick the nanners... if you go with misting, maybe 1x daily? but still pick nanners!!! and keep humidity way down so the moiture evaporates too fast for mold to grow.