Is it normal for a bearded dragon to bury himself?

Hi, yeh this is normal behavior, mine does it too sometimes, its known that bearded dragons like to bury themselves in the sand in the afternoon to help them cool off while they wait for the night time when its cooler, they dont always do this. I know you said he is burying himself in the hot side but that doesn't really matter, he is still wanting warmth, more then the cool side is giving, just a wee bit less then the full heat of the hot side. but it is most likely that the hot side is too hot for him just now so if you can,lower the temperature of that side of cage, maybe raise the height of the lamp away from the viv to decrease the amount of direct heat.