A surge during Af?

Has anyone ever took a opk during a bleed they thought could be af and got a positive opk? I read that during menstrual flow the tiniest lh hormone is present so you won’t even get a positive opk. So why am I getting a full blown positive and I’m spotting? Also I started spotting 3 days before Af, so I’m 3 days In my “cycle” / maybe “implantation bleeding”

My question is has anyone gotten a positive opk while on their Af?

My opk was darker right now, than when I actually took it during ovulation.

Any feed back is appreciated!!