For some reason TR interior tent doors sometimes do not match the rest of the tent, and the gap to the void of the interior is visible in game.
I don't know if it's something prepared for yet not implemented feature, like for example showing some ground from the exterior while being inside of the tent, but I've noticed that several times.
Happens in:
Velk Camp interior
Urvel and Hanneth's Tent
Ulyn Menathren's Tent