Appraisal or IV calculator messed up

I have a Metagross that seemingly broke something. It has 2996 CP, 123 HP and the appraisal tells me that ATK and DEF are the highest stats and both are 10-12. The Metagross isn't weather boosted and it's either level 29 or 30 (power up requires 5000 dust).

The problem is that according to GP's IV calculator that combination of stats and appraisal isn't possible. Trying out some values for level and IVs suggests that the Metagross is level 30 and has 9 HP IV. Going on from there I get these results:
11a/10/9 gives the correct CP, but it doesn't match the appraisal. On the other hand
11a/11/9 matches the appraisal but the CP isn't correct.

I found this quite curious.