If people use their old test for line progression wouldn’t that be like a false positive?

So I took two test once a week. The first one had too much pee but I seen a faint but noticeable line the second week a still seen a faint line but I used less pee. I was watching YouTube videos and people were using their week old test for line progression and it was a faint line. Wouldn’t that be a false positive considering that looking at a test that old can dry up and develop an evap line or an indent? Sorry I’m new to this pregnancy test stuff.

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