I noticed him doing this a couple days ago, too.
If i put out fresh greens, they dry up uneaten, and still he won't touch them.
This evening i gave him a soak, he had a good bowel movement. I was out of store-bought maggots and there are no grasshoppers out yet, so i tried to feed him a defrosted grasshopper. He snapped at it a couple times without result, so i tore it apart for him, but then he was no longer interested. (He did eat one a couple days ago, or part of it, but that one had lain in his warm dish, ignored, for days.)
So i put the grasshopper pieces in his dish in his tote, and set him in front of it. Next thing i knew, he was noisily eating this dry leaf. I don't think he actually swallowed much.
At the very beginning and end of the vid you can see a white ball. That's calcium carbonate. He has never touched it, nor the cuttlebone i previously had in there. Yet his shell has always been hard.