The only problem with high humidity is the actual moisture of it. If there is condensation forming inside the hide from the moss, I would remove it. However if there is not, and he seems to like it, it's fine.

In the wild Ball Pythons make their homes inside termite mounds, which are very very high humidity...90-95%, but since their isn't actual moisture in there they are fine.
(This is something I have read on this forum before, just can't find the thread right now)


If they prefer this in the wild, I would say its fine in captivity.