Me and my friends were toying around with replacing existing Minecraft biomes with our own custom biomes using Datapacks. What we would do is use in-game custom commands to set the biomes of a selected block region, which in this case is usually a Minecraft biome but it'd appear as our custom biome because we overrided it.
They worked fine most of the time, however sometimes the biomes would cause an "Invalid biome id: -1" in our Client consoles, and cause us to lag massively. Whenever we reopen the server, the custom biome would be gone and the land would be reverted back to its original biome.
This also occurs sometimes when we're not even around the biome, and it would be reset even though no one was around.
Attached is what would happen whenever the biomes disppeared, and also the Datapack that we compiled to override the Minecraft biomes.
Please check if this is still an issue in 1.17.1 or later.