Sorry for necro-ing, but I also have this issue. Turning Vanilla Bosses on and off seemed to work for a minute, until it then didn't. I have no idea how to fix this.
RE: [MODDED] Bots stuck in place.
This thread describes how OP fixed their issue, but your mileage may vary due to different mods being used and whatnot.
I ran into a similar situation yesterday myself, except the AI in my raid (except the friendly PMCs I spawned with) had no bodies to speak of - if you looked at them you'd only see a floating gun and armor/gear. I removed the friendly PMC mod and that seemed to fix it, so I'd say try that and see if it works. 
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