Evap line?

Hi! I posted on here yesterday as I got what I thought was a very very faint line on a Clear & Simple test. I did another test today and got another one, but a little darker. However, I was feeling a little unsure about this brand of test as I got faint lines on them last month too (assumed it was a chemical) so I used another test and dipped it in water. And there’s a faint line on that one too! Here are the 2 tests (I took them out the plastic to see better but took photos immediately and lines were evident even with plastic on). Top one is with urine, bottom with water. Given that both have lines, should I assume it is just an evaporation line and negative? (Never using this brand of test again!)