Hi hjp- Welcome to the world of beardie slavedom. They can drive you crazy can't they? He could just like the feel of the dish. Barbar's Checkers loves to brumate in his dish all winter! Of course there is no water in it. :lol: I still can't figure out how he curls up and fits himself in there!?! :dontknow:
If it were me I would take him out and empty the dish. I doubt the humidity is such a problem this time of year but, yes he could be breeding all kinds of germies in there and you don't want him to drink it now. ewwww! You can put the empty dish back in, just in case he feels comfy there.
He may need more frequent baths because the humidity is soooo much lower in the winter house.
What are your temps and how do you take them? As the others said he may be too warm.
On a food note, try hin on some cilantro, mine can't resist it and it is really good for them. It's cheep and will give a bit of variety. Mustard greens are good too. Of course, depending on where you are mustards may be hard to find. Lots of folks here say their dragons love butternut squash. You use a food grater on it and use it as a salad topper.
If you could tell us a bit about your set up and your dragon's age and size it would help us, help you. Oh, and what's his name. I know it doesn't matter with the problem, I just like to use names, for dragons and people too.
Sandy H