Affects Version/s: 1.15.2, 20w19a, 1.16.1, 1.16.4, 20w51a, 21w03a, 1.16.5, 21w05a
Fix Version/s: None
Although enderman can place pumpkins on top of snow to create snow golems, the same cannot be done for wither skulls to summon the wither. For the same reason, repeaters/comparators don't update their power state when placed.
1. Download the provided world. It adds wither_skeleton_skull to the enderman_holdable block tag, allowing endermen to pick it up. It adds air to the wither_summon_base_blocks block tag, allowing the wither to spawn almost anywhere.
2. Place a wither skeleton skull manually next to one of the many piles
→ The wither spawns and is immediately killed by the running command block
3. Wait for an enderman to place down the skull it's holding
→ No wither is spawned
without running Block.setPlacedBy, which causes the block to not update correctly.
It can be fixed by adding