What should happen:
Lukewarm with cod and pufferfish

What happens instead
All lukewarm ocean mobs, but with salmon instead of pufferfish, according to Minecraft wiki, pufferfish should spawn in lukewarm ocean, but salmon doesn’t

How to reproduce
Find lukewarm ocean seed (I used ‘survival islands’), and go to the lukewarm ocean
Biome: you will find cod, squid, dolphin and salmon, but no pufferfish, but salmon instead.

Extra info
I think that salmon replaces pufferfish, but that spawning might be an another bug
Also deep variant is affected