Arma 3
Advanced Rappelling
Enemy AI breaks on Dedicated Server
I love this mod, one of my favorite for my SP games.

I did find out though that it was breaking the enemy AI on my dedicated server. If you use this mod and find enemy AI is spawning in squad sized clusters and not moving, this mod could be the cause. The enemies would fire and lay down etc but they would never move from the cluster they spawned in as, would not take cover or path anywhere. This seemed to happen with most, but not all enemies. Enemies that spawn with a vehicle seem to be okay. Removing this mod fixed the issue for me after finding the suggestion somewhere else.

This issue does not exist in SP and from other form posts it seems to not exist in Hosted MP (but I haven't tried that). The bug occurs on dedicated servers.