Glow prediction totally off

Hi all,
​I use myNFP and Glow simultaneously and ovulation tests. I noted that Glow is off by a few days when it comes to my ovulation. How can this be corrected?
​Example from this month: ovulation test positive: Thursday and Friday. Basal temp increase: Saturday. Glow thinks the best chance to get pregnant was Tuesday. I don't think so....
​I have the feeling glow uses a standard value of 14 days to ovulation, but I already changed my data to a 32 day cycle.
​It would be great if you have some advice!!! Thx!