Affects Version/s: Minecraft 17w48a
Fix Version/s: Minecraft 17w49a
Steps to reproduce:
1. Get yourself a playerhead in 1.12.2, e.g. with:
2. Put it e.g. in your hotbar.
3. Go into the current snapshot (17w48a), notice that the head is not called "Meri's Head" anymore, but "block.minecraft.player_headnamed".
This does not affect custom heads, e.g. try this command in 17w48a:
Custom player heads are successfully updated to "player_head" instead of the faulty "block.minecraft.player_headnamed".
For that I went into 1.12.2 first, packed my hotbar full with those custom heads, then I opened the world in 17w48a.
Also @Mods please do tell if I should open an own bugpost for this:
I used this give-command in 1.12.2: