Leave him alone- he's doing what he wants- & if the log-hide is in the middle, it's likely the "average" temperature he's wanting right now. On the whole, my snakes spend more time in "cool" hides than they ever do in "warm" hides, if that eases your mind any? And I also use a few "log" tunnels just as extra furniture too, for some of my snakes- I place them snugly in front of their warm hides, so the doorway of the warm hide opens into their log tunnel- sort of like a "covered patio" that ends up being a mid-range temperature.