Mob Spawn issues

I currently have a mob spawn issue with sponge and lycanites mobs. Basically if there’s 2 players in the same location, it spawns double to mobs. 3 players triples the mobs and so and so. I’m sure this is caused by sponge because when I remove sponge from the server, mob spawns work normally. Can anyone help with this?

Do you run any sponge plugins or just tried it with spongeforge?