Positive opk before AF

I ovulated CD 17 as normal confirmed with BBT digital OPK and IC OPK all said the same. I randomly tested again around 6dpo when my tests would normally go back to completely blank not even a hint of a second line even. This time my tests have been either positive or close to being positive this has now happened for over a week. I’m due AF tomorrow. Is it normal to have constant positive OPKs after confirmed ovulation? I’ve been TTC 3 years and this is the first time this has happened.