Minecraft 1.11, Minecraft 16w50a
When a moving block moves entities its bounding boxes are chosen as if it was placed at 0,0,0.
If 0,0,0 is not loaded for the client that also can lead to client/server desyncs as it will see air, opposed to the server which loads it when it does the check.
Way to reproduce:
The armour stand gets moved up even though it is not inside the collision box of the fence.
Note: there should be solid blocks around 0 0 0 (so a fence at 0 0 0 could connect to them)
To fully fix this
MC-110094 would need fixing, but at least making it dependent on the current position would remove the client/server desyncs it causes (and it would be a less random source for the actual state at least).
- Cobblestone Walls