Player locks up on larger change in terrain elevation

I have a rather large elevation change in terrain in my game. While the terrain is walkable, when my player reaches a certain depth it locks up and will no longer respond to game controls. Does anyone know what causes this?

I was finally able to figure this one out for myself. It had to do with the “Kill Z” value in world settings. If you game map has extreme elevation changes your character and game will lock up if you traverse below the setting value in Z.