Reply to MadMan25 - I'd guess you could still make a farm if they disabled spawning directly in bubble columns but having space between the bubble columns. But currently it's a bit annoying having fish spawn in a water elevator.
This also impacts 1.18.1. I also have a soul sand water elevator from the bedrock layer which goes through a Lush Cave biome. Tropical fish spawn in the bubble column and get brought up to the top of the water elevator.
I've attached multiple screenshots of the bottom, top & middle section that runs through the Lush cave biome.
I'm also seeing this same error on my server running 1.21.1 but it is a modded server. I'm not sure if a mod is causing this or if it's just the base game.
Server log: https://mclo.gs/zFfdFtW