hello!, i got a problem with my mech, so apparently you cant attach players to a rig as it screws up collision, but i have to do that, or something similar, and if i do that it just ends up like this due to collision(i tested with a normal big dummy too, and it happens even if i use collision groups)
Have you tried checking the humanoid hipheight property?
I did, it was at 0, set it to 1 and its the same