Yes, that is just thermoregulating. As to the height of your enclosure, I have to ernestly suggest something much shorter. A 20 gallon long tank is a great start. My first BP was constantly doing the wall climb with a loud thunk when he lost his grip or strength. It worried me so much, even with perfect temps, regular feedings... I decided to move him out of that tank as soon as possible. I went to tubs and havent looked back.
Anyways,
The fall itself could severely hurt him. Not to mention if he fell on some cage furniture, he could end up with broken ribs, internal damage and quite possible death if he fell just right.

Bp's are not very good climbers and are best in a short but wide and deep tank. It's the safest when they cannot climb up and fall over like a tree. I hope you have corrected that.