Yes, managers do make mistakes over the course of a season, but this is a trend with Gibbons. Whether it's Francis in a close game, or Schultz, or Tepera, or whoever. He either abuses Osuna, or when he can't, he'll bring in his 7th reliever in the same situation. It doesn't make any sense.
He is s*** when it comes to managing a bullpen (and a lineup, and a defense, and practically everything else other than making people laugh in media sessions).