The app doesn’t know your body or when you ovulate or if you ovulated. Too early for ib so it’s not that. If you want accuracy you need to actually track your cycle with opks to let you know when your about to ovulate and BBT to confirm ovulation and you will know when you ovulated, dpo, luteal phase length (is from the day after ovulation to period which stays the same each cycle give or take 1-2 days. Average length is 12-14 days give or take 1-2 days.) when period is coming by temp drop or if you miss your period and your temp stays up then there is a chance for pregnancy

Actually spotting can occur before and directly after ovulation, I use this app to keep track of my period and ovulation. I’m implying this is most likely implantation blood or a tiny bit of breakthrough bleeding.