Evap line?

Has anyone took a dollar store test, seen it was negative within the first 2 min, put it to the side and seen a faint line later and turned out to be actually pregnant? I know it's most likely an evap line but I've taken dollar store brand tests before and never have I got a faint line a moments later, it was always a solid negative. So I'm just a little confused. Not getting my hopes up of course. I will be testing on Friday with a better brand. I'm 2 days late BTW.