Why did my fertile window change?

My last AF came on 12/22. It was a 25 day cycle, but also my first cycle off birth control. At first Glow had my fertile window pushed back in my cycle(like "normal" 28 day cycle would look like), and then yesterday it updated saying I had already O'd and that my predicted cycle lenght was 22 days..? Why would Glow do this? It there a way to change it? I may have had a short cycle last month but I have NEVER had a 22 day cycle like it's predicting. I'm just wondering if there is a way to adjust it on here because it's wrong. TIA!