you can walk through any block on 1.12

Cannot reproduce after fixing some code style. Guess was a code style issue.

Most(?) of the AABBs lost their position offset, the port likely didn't account for this yet.

Ah thanks @sfPlayer1. Luckily the mod uses an interface to account for aabbs for tile entities, that would not be very hard. Do you mean those ones which have their World parameters changed to IBlockAccess?