I am aware that this has been mentioned, but I think it needs a bit more information.
As soon as I make a new world, with JUST spirit mod installed, the entire purity over world has what I believe is the "spirit biome" background. However the music doesn't play. Like NO music at all. Not only that, but it's also overriding biomes it shouldn't be, such as the dungeon or the corruption. It's actually beginning to really annoy me. For example, in the 1 minute it takes me to get from the overworld, to the bottom of the dungeon, I have no music, then spirit music, then dungeon music, then no music, then spirit, then none, then dungeon, and it changes between those 3 in a split second. Very frustrating. I am in love with this mod tho! So please don't take this is a harsh criticism. I also don't have an overworld, or underworld spirit biome. Just the music and the background. Nothing else. I am not sure on if this is something you know of yet or not. I just wanted to let you know. Unless this is something that happens in hardmode like the hallow, in which case, the lack of a spirit biome shouldn't be changing the background or the music (or in my case muting it randomly) if it's meant to be unlocked for hardmode
Also, these enemies (Not the trident, the other two) are spawning in the dungeon in large numbers. I also don't get the mobs that are supposed to spawn in the dungeon, on the lower levels. Is it possible that these hell mobs are over riding the dungeon ones when the player gets town too far?
This is all pre-hardmode I might add. And I usually play with Thorium, Clamity, Tremor, Spirit and EnemyMobs. But those are it.