Opk- a tale of two tests

Took a Clearblue digital opk and a strip opk to make sure I'm ovulating- I like to see the hormone levels getting darker on the strip test then I'll confirm with a CB digital opk that it's positive since they're expensive and I have a very hard time reading a true positive on the strip tests. My strip test looked positive yesterday and I had egg white cm but my digital tests have said no since yesterday morning. I took tests yesterday morning with fmu, at 3pm, and at 8:30pm. I just took another set of tests and the digital is done processing and it's still negative! I had major cramping yesterday around both ovaries so I was pretty sure a test would've come back positive in the last 24 hours but nothing.