The smaller door of the two large doors is not enterable, the other doors on the side of the building work fine. I have tried to enter in multiple poses such as walking/running and gun up/down. See steam pictures below

Trying to open the door you want is also very frustrating as you could open 1 of 4 doors (one on the inside) and 25% chance of getting the door of your choosing to open.

Should also be noted that this is on Altis - this applies to any of the same model.