Hey there, I had an issue where I would remove an NPC, reload oxide or restart the server and the NPC would re-apper. The NPC looked like it was standing, but was up off the ground a little bit.  The last thing I tried that fixed it was editing the NPC with "/NPC_edit", "/spawn 99" and it moved to me with the message "NPC Editor: Set spawn to 99" then I used "/npc_remove" reloaded oxide and it stayed gone. Hope this helps, I'm posting because I read all the other issues first and they did not fix my problem.

when your remove an npc if you reload it will come back humanNpc saves are on a timer so if you would wait say 5 min befor the reload then they should not come back.