Glow changed my percentage?

Kennedy • Married to my soulmate since 7.4.2020!💍💞 We have a 4 year old son, who took a year and a half to conceive! We are expecting baby girl March 11th 2021 after 2 1/2 years of ttc with fertility treatments 💖
I just got on today on went to do my daily log and today is supposed to be my peak day, at 33%. And that's what it said. I logged, came back and it said today was my 27% day. If been knowing since I started my period that today was supposed to be my 33% day.. Now yesterday was my 15% day and today's my 27% day instead of my 33% according to Glow. Anyone know why that happened? It just changed all by itself.