I think this may be partially true, but not completely. Bubba certainly doesn't give off the killer instinct himself, but I think the lack of putting teams away is usually more due to the lack of talent to be able to do it, along with situational play calling. He has certainly had some games where putting teams away has not been a problem, it just isn't consistent, and I don't think we are always capable of doing it.
2015: UND over N. Colorado 45-14; UND over Team Joe Protheroe 45-21
2016: UND over Sac St. 40-7; UND over S Utah 45-23
2017: UND over Misery St. 34 - 0; UND over Portland St. 48-21