When I look at your profile, you don't have any missing hidden dates and the hidden dates finder page agrees that you don't so everything seems OK.
What fools you is probably that the profile page isn't generated every time you look at it, but all other pages are. This means that the profile page may be slightly out of date, so if you have found a cache hidded on the last missing date very recently this situation will appear. By now when I look at your stats, Project-GC has regenerated your profile stats and everything is in sync again.
The profile stats are regenerated daily if you are a paying member of Project-GC and weekly if you are not.