Ovulation question / OPK

I’ve always tested with FMU. Last week, I got a solid smiley face (Clearblue digital) - but it was ten days earlier than my normal cycle! I usually ovulate on CD20-22. This happy face was CD13.

I was confused so I held my pee for four hours and tested again later that afternoon (around 1pm) and it was a blank circle.

I’m NOW at CD22 and no LH surge yet so now I’m wondering if ovulation already occurred …

Has anyone had only a few hours of a solid smiley?