MC|ItemName is an unknown channel. (Related to Anvils)

[FastFelix771]

When i click with an item into a Anvil, the following message appears in the console: (removed log level etc.)
FastFelix771 used unknown Minecraft channel: MC|ItemName

The minecraft client probably sends some packet(s) that acts with anvils?

EDIT:
This happens on EVERY action in the anvil.
Even if i wanna change the item name, on every letter i enter, the message appears.

---

Want to back this issue? Post a bounty on it! We accept bounties via Bountysource.

[FastFelix771]

If i repair a enchanted diamond pickaxe, this thing appears in the console:
[rejected] WindowClickMessage(id=11, slot=2, button=0, transaction=21, mode=0, item=ItemStack{DIAMOND_PICKAXE x 1, UNSPECIFIC_META:{meta-type=UNSPECIFIC, enchants={DURABILITY=3, LOOT_BONUS_BLOCKS=2, DIG_SPEED=4}}})

Also, i get the repaired item, and the broken one.
Items duplicate.

And randomly, it also deletes, the broken pick, the new one and all 64 diamonds from my inventory.

[aramperes]

Partially fixed in 2aad4f0