Bearded dragons respond differently to having their tanks rearranged, and being put into an entirely new tank. Since you just put him in his new enclosure last week, and since this behavior just happened since putting him in the new tank, I would guess that he has some relocation stress and needs to get acclimated to his new environment.
When I moved my 7 month old Scarlet from a spare room to the bedroom, she started hiding on her cool side and trying to sleep in any dark area of the tank. She stopped basking all together. I have a new ReptiSun 10.0, my temps are perfect, yadda yadda. She was stressed and it took about two weeks for her to behave like her old self.
When I would see her hiding or sleeping in the dark corner of the cool side, I would pick her up and put her under her basking lamp or on her hammock. I did that maybe 4 times a day. She's fine now. I would give your dragon time to adjust.