Affects Version/s: Minecraft 16w42a, Minecraft 16w43a
Fix Version/s: Minecraft 16w44a
When a piston pushes the player when sneaking on a block that is being pushed by the same piston, the player will phase into the block.
steps to reproduce:
1. build a piston mechanic like the picture below and stand in the same position as shown in the picture below.
2. activate the piston while sneaking.