Does your cycle change as you log?

Does your previous cycle information change as you log? For example, in Oct. I marked down we had sex without a birth control method. When I marked this my risk of pregnancy was very minimal, like 3% like always. After I got my period that month I logged when it ended; when I did that it said the day he came in me was my ovulation day? Obviously I didn’t get pregnant BUT has this happened to anyone else? I know this app isn’t 100% accurate & at this point we’re not actively trying or caring to much about preventing but I really do enjoy using this app to track my periods & possible ovulation.