It’s just a faulty test. Sometimes they aren’t made right. I would try a different test
@Kristian Larger every clearblue has them underneath even before you dip it in the wee ,next time you buy a clearblue look at it in the light ,it just how it's made x
The line is always like that when you shine it into the light ,it's just shows the test worked x It's just the mecisnm underneath it's supposed to be like that I'm pretty sure x