I had a similar problem a few months ago. He had been in that enclosure for 6 months or so with no problems, temps all fine but he spent a few weeks being seriously stressed and trying to get out, I had to pad the gap between the cage and the sliding doors because he was working his head into it so frantically he managed to scrape his chin (healed up nicely now). It stopped just as mysteriously as it started but was very worrying for a while. He is his usual sleepy self again for the last few months.