This is very interesting. I wonder if this is another condition that abuses the stair-stepping bug ( [Client] Walking against a wall incorrectly triggers stair-stepping logic ) and creates another wall climb technique.
I think this is distinct enough to not be a duplicate of Stair-stepping bug + Shift Locking allows you to climb walls - #3 by Thanark because while this stems from the same bug, it is a different repro condition that involves a small space where you are squeeze between the walls, so they are constantly fighting to push you out.
What game are you playing where the bug occurs?