Try turning off the thing that makes your character sheet popped out. You can't interact with the compendium when sheets are popped out, so I suspect the NPC can't access the data to be created properly when the sheet is popped out, giving the result you have. After a NPC is created/drag-n-dropped, there shouldn't be an issue with having the sheet popped out. For more on limitations when sheets are popped out, check: <a href="https://wiki.roll20.net/Character_Sheet#Character_Sheet_in_a_separate_window" rel="nofollow">https://wiki.roll20.net/Character_Sheet#Character_Sheet_in_a_separate_window</a>