If I get too close to a zombie sometimes I get locked into their hit box frame. This happens with doors when trying to open them when getting attacked or fighting zombies. Fences and walls when trying to vault over them when getting attacked by zombies. Or if I go from standing to crouch (this does not always happen but you basically get trapped inbetween the objects and the only way to get out of it is by continously running and even that doesnt always work. When it happens during standing to crouch the only way ive been able to get out of it is by going prone.