He's probably fine and he's probably thermoregulating, which means your husbandry is good. A snake gets too warm and he'll move to a cooler area to "cool off". A snake gets too cold and he will seek warmth.

I find Carmen coiled up outside her warm hide but under a large leafy in the morning, but sometime late afternoon, she'll stretch half her body out along the back of the viv, behind her water bowl. The next morning, she'll be coiled up again. Just moving around to adjust body temp and check out what's going on. =)