Client easyly Fall from thin block, ladders, and jump to water

Im testing in in multiplayer mode, im play as host of world, and my friend play as client. When my friend go down with ladders, he is take big damage, or dead.... When jump from oak tree, same, take big damage...... I don't testing the last, that is jump to water..... This bug is in minecraft in all 0.11.0 build/beta version

Tested in Evercoss A26B, Acer Liquid Z200, and Advan s5e