Ovulation date changed?

Claire

So my period is 12 days late, so I have been updating my status on Glow. Now this morning I updated it to reflect that I have not gotten my period. Originally my ovulation dates were late August into early September for Labor Day weekend (in the U.S.). Now Glow has switched my ovulation date to the 2nd into the 3rd week of September, I guess to reflect why I haven't gotten my period. Has this ever happened to anyone ?