When using the "remove" command on mobs and readding them to specific biomes, the old biome weight entries are still there, so those mobs get ADDITIONAL weight entries. You can verify that using the mod "TellMe" and dumping all biome weights entries to a file. I attached that dump for reference.

potentialspawn.json
[ { "remove": "minecraft:squid" }, { "dimension": 0, "biome": ["minecraft:ocean", "minecraft:deep_ocean", "minecraft:warm_ocean", "minecraft:deep_warm_ocean", "minecraft:lukewarm_ocean", "minecraft:deep_lukewarm_ocean", "minecraft:frozen_ocean", "minecraft:deep_frozen_ocean"], "mobs": [ { "mob": "minecraft:squid", "weight": 25, "groupcountmin": 1, "groupcountmax": 2 } ] } ]

biomes-with-mob-spawns_2021-01-20_16.33.04.txt