The Metropolis trait doesn't seem to work, like at all.
Played in a story and a random map. Had no lockouts except for when taking over cities.
Pop bonus seem to work but structure bonus counts wrong.
Annexation bonus seem to work.

The Forest Temples from Ancient Druids seem to be transforming annexed water tiles to forest as well. It's possibly an interaction between the Colossus Moon event, which changes terrain to swamps, since that was going on when I noticed. The end of the event page indicated that none of my provinces had been effected though, so idk. Not game crashing, but I do have a fish farm in a forest now.

Druids - This one is weird. It looks like it terraforming only existing forest to... forest but with other texture. 0 new forests, but trees in existing forests looks diffrent.
Didn't tested rest of traits.