Not being a big endorsement fan myself, this doesn’t effect my opinion of her. I do know that Mittens got in there to help her when she was running in that tough Primary. If Palin was running, I would guess she would have endorsed her instead considering that she gave her the same boost in that Primary.
This is the main reason that endorsements are a joke to me. They are usually just traded favors among pols. I can’t imagine any thinking voters leaning toward some other candidate switching to Mittens on this backing.