so my fiance noticed this and mentioned this to me and since we just started doing this app on my period last month I wondered if this has happened to anyone else. so my period was on the 14th of June and my ovulation date ended up being after my birthday on the 26th because we took the test. and my period was predicted to be on the 10th of this month. everything was all good till he noticed that today the period time changed to the 13th and my last month ovulation date was the 29th which is not right has that happened to you too where it changed on you.