Affects Version/s: Minecraft 18w08b, Minecraft 18w09a, Minecraft 18w10d, Minecraft 18w11a, Minecraft 1.13-pre1
Fix Version/s: None
The following advancement use to work in 1.12.x
From the wiki:
The villager the item was purchased from. The 'type' tag is redundant since it will always be "villager".
However in the 1.13 snapshots, the type tag is now required. The above advancement only works if you add the redundant type field:
This bug seems like it was introduced due to the changes which were made in 1.13 snapshots to the way entities are registered and constructed. It doesn't seem intentional and I haven't seen it documented in the release notes