Cycle length incorrect?

Ashleigh • Gave birth to my first on 2/21/15. Lincoln James. 💙
Why is Glow saying my next cycle will be 29 days even though I input that my cycles were 28 days and this month it was exactly 28 days? Glow was predicting a 30 day cycle and had me starting AF on Saturday for whatever reason, however AF came today. I logged that but it is still giving me a 29 day cycle this time around.