Thanks for all the help, I took him out and the spots actually wiped off!!! Looks like it was collected deposits from him sleeping under plants and water dripping on and collecting on his casque! Even though the water was RO, the tap water in the humidifier must have caused it. Thanks again!
I am using RO water in his automatic mister and hand mister, but am using softened tap water in his cool mist humidifier that mists his enclosure all day. Without the humidifier here in Michigan right now his humidity was too low so I added it to get the humidity reading correct.
Please take a look at this picture and let me know what you think may be wrong. He just got done shedding a two weeks ago so I am pretty sure he wouldn't shed again already. He is an Ambilobe about 6 months old. Using a Mercury Vapor light, basking temp of 90, ambient temp gradient down to 70...