Confused.

I'm so confused. My cycles are normally 27-28 days. This cycle I got a peak result towards the end of my fertile window and glow pushed back when my period was due. Glow says my period isn't due until Saturday. Today would be eleven days after I ovulated meaning it could be a possible implantation day. I am experiencing some light spotting brown spotting and mild cramping. If I hadn't ovulated later, the app would say my period is due tomorrow which would be cycle day 28 for me, a normal cycle length.

So if you ovulate, enter a peak result in later does that mean glow thinks your period will come later and your cycle will be longer than normal? Trying to understand how this works.