So basically I was trying to make my own modpack for my friends and during testing I noticed that whenever I went into the server the mobs are unable to do anything (except for flying mobs for some reason such as bees and flies, they can move just fine) It's only the ground mobs, the strangest part is that everything else works EXCEPT the mobs, stuff like furnaces, blocks and such work fine, only ground mobs refuse to budge. What I also noticed is that whenever I try to push them or hit them, they cannot move out of the block they spawned on, as if they are surrounded by invisible barriers. Another thing is in singleplayer the usually affected mobs actually work just fine, it's just when playing in a server, they dont move at all.

https://www.mediafire.com/file/okyrnd208pil6rw/latest.log/file latest log from start of server

Maybe an issue with performant or theabyss

I'm having the same issue rn. Hostile mobs wont move until attacked but peaceful land mobs wont move at all. If it swims or flies its unaffected until it touches blocks.

Since flying mobs like bees and flies aren't affected, the problem likely lies with how ground mob AI interacts with the server environment. Checking the server logs, as you've done, is a good step. You might want to look for errors related to mob AI or pathfinding. Consider removing or updating mods one at a time to isolate the issue. Additionally, ensure your server's performance isn't being overly taxed by the modpack, as this can sometimes lead to unusual behavior with entity AI.