Can someone explain this

Neisha • Mommy of 4, my angel baby arrived on 5/11/2020 engaged to the love of my life 💍

Okay normally my cycle 25 days past two months before it was like 28 days or so..initially cycle was due 1/20 I end up getting blazing positive opk again on 1/12 n 1/13 but y the hell FF saying i am 4 days late for period?