I believe it relates to hitboxes glitching around, similar to the graphical glitches of mobs being seemingly pushed through the walls. They gravitate to corners because the game is still assuming that the holding cell is filled with the hitboxes of the mobs, meaning once they find themselves in those corners, it's impossible for them to move. This behavior is progressive, as you can see it happening with fewer mobs but becomes so extreme with higher quantities that you can no longer see the visual representations of the hitboxes that are causing the effect. I just can't imagine how this glitch could be fixed, aside from forcing mobs to not stack on top of each other.
Myufi Blackketter
I believe it relates to hitboxes glitching around, similar to the graphical glitches of mobs being seemingly pushed through the walls. They gravitate to corners because the game is still assuming that the holding cell is filled with the hitboxes of the mobs, meaning once they find themselves in those corners, it's impossible for them to move. This behavior is progressive, as you can see it happening with fewer mobs but becomes so extreme with higher quantities that you can no longer see the visual representations of the hitboxes that are causing the effect.
I just can't imagine how this glitch could be fixed, aside from forcing mobs to not stack on top of each other.