Go up to a player and push them. Then, between -9.5 to -37 (When looking at the F3 menu: pay close attention to Facing. The two sets of numbers in () the first indicates the angle from side to side, the other is up and down. The up and down direction is the one you want to pay close attention to. When between these two numbers, the player you are looking at will disappear from view between those two angles. I've did some extended testing and it appears that it only happens on y level 95.