Do you have two identical hides? If not, it could be that he's uncomfortable in the warm hide, but doesn't feel comfortable enough with the other hide to spend time in it. You also mentioned deep cleaning once a week, could you give us a few more details about what you mean? To me deep cleaning is removing substrate, wiping down with cleaning solution, the whole deal.

You also said you handle every other day, did you give him time to settle in before you started this? Typicall it's recommended that you let snakes eat three times back to back for you before you start handling to let them get use to their new home.

The last thing, the heat mat that you have under his warm hide, what's the temprature on that, how are you checking it, and do you have it running on a thermostat? You said it was covered, do you mean by the hide or by substrate?