Clearblue Advanced Fertility Monitor

Hi everyone,
I'm using the Clear Blue Advanced Fertility Monitor for the first time and this morning I got my first 'high' reading. When I pulled the test stick out, it didn't look like the urine had fully moved across the test window. I know you aren't supposed to read the test stick, but it didn't look complete. 
I'm questioning it because I got a 'high' on CD 8, when in my last 6 cycles the earliest I've ovulated is CD 22 (based on bbt).
Has anyone else experienced this?