Grading is tough to figure out I have learned since joining. Just when you think you have it down pretty good to where you believe you could grade a card within 1 or 2 grades of the TPG's, another graded card comes along and throws a wrench into everything you thought you knew.
I think everyone on this board has a card or 2 where the grading just doesn't make any sense, and with that being said, it is just something we have to expect every now and then.