In survival mostly youwikk see these lines that seem to try to move to the center of screen where the split touch cursor would be. They do the same thing without split touch controls. This doesnt happen that much in creative but it does happen sometimes. The lines seem to affect mobs too as there is lines pointing random directions on them which is really weird. This also affects hostile mobs as some zombies are missing some limbs,which is actually pretty cool,and the hostile mobs also have these lines. There is also texture glitches that cause these lines such as the tree texture spreading spreading but its really not there.