It's possible that another mod is interfering with this (I wouldn't know for sure as I'm running total of 14 mods in this game), but it seems that Human Genome Project wonder from World Congress project is, rather than giving 1 extra culture per turn to artist, musician, and writer specialists (thus 4 culture per turn from 3 of non-modded game), changing culture output of those specialists to 1 culture per turn.

https://i.imgur.com/IZDpfIW.png the same applies to other two specialist types. This isn't a big deal since ~35 culture per turn isn't a huge amount versus what the empire should be producing at this stage, but it's still not what the wonder intended to do.

And for the record, +1 output for engineer, merchant, and scientist specialists seem to be working as intended.