OPK confusion/help

JT
Hi Ladies - Would love your thoughts on this. i'm at CD 21 which is late in the month but i tend to ovulate later. Last month I ovulated at CD 20.
I've been using the Clearblue Advanced Fertility OPK and also cheap ones. This morning, it seemed like the cheap one was positive, but I still only had a flashing smiley.
Thoughts? Also - my bbt has dipped yesterday and today.
I'm just confused. I was worried I wasn't going to ovulate this month but I've been tracking since July and have always caught it.
NOTE: I know you can't tell from this pic but the smiley is flashing not remaining on the screen which means high fertility not peak.