If your animal is losing weight, my guess would be that it is dehydrated. Humidiy doesn't hydrate an animal, it merely slows the rate of dehydration. If the animal is not taking in fluids, it will continue to dehydrate- perhaps at a slower rate than in a bone dry enclosure, but nevertheless, it will continue to lose weight/dehydrate.
Dehydration is the #1 cause of ailments and deaths in captive reptiles, especially wild caught imports. I would make sure that it is volountarily drinking fluids when sprayed/rained upon(many will not drink from standing bodies of water), and then go from there.
Also, telling us that your temps are humidity levels are "ok", doesn't really tell us much about what they are...
But from the sounds of it, it seems as if your animal is suffering from dehydration.
Good luck,
Bob
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