Have you treated for mites lately? Switched to a new disinfectant or cleaner lately?
It has the ear marks of poisoning or a neurological disorder. HOWEVER it could also just be odd royal things one of mine likes to try to balance on his door top and will fall, he then starts all over again.
If you are certain there is not poisoning possible (that includes flea treatments esp pyrethroids) it could be nothing at all or even OCD it happens sometimes in captive animals. If you can rule out the other things you could try some enrichment, I use a ping pong ball just rub it on something different, like your car seat and transfer it to the enclosure. New object new smells mine often investigate them. After a few days I remove it and add something else.