Pregmate evaps?

I’ve never had an evap on a pregmate test before (after TTC both of my kids using pregmate). However the last two days I’ve seen the shadow of a second line during the proper timeframe to view test results. After that the test dries with what could be an evap or a true second line. Again, when I used this brand before, when the test was negative, I never saw anything when the test dried— stark white. I don’t know how many dpo I am as my SO and I weren’t TTC; my period is irregular and I started wondering if I had gotten pregnant.

Has anyone else experienced this with this brand?? Could this be the start of something?