Change in Ovulation?

Sa

So i updated my <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a> last night. Before the update it said I would ovulate Tuesday now it says I ovulated Sunday. I’ve been taking ovulation test so I know that i didn’t ovulate Sunday cause that’s when I started but still just wondering if anyone experienced this?