Hmm well your humidity is on. I was thinking that if you were using belly heat that it could be drying out the substrate too much and not giving you an accurate humidity reading, but you've got it coming form the top. I mentioned the perch thing just so it didn't seem like mine was constantly stuck at 75*.

I noticed you also posted this on AA, so you will definitely get more experienced opinions on there. From what I know, if you are sure your humidity readings are accurate, and there's no mites, I would lean towards it not being a big deal. But keep it up on AA there's a wealth of information from experienced corallus keepers, you'll get to the bottom of it!