There looks to be something faint on all of them except for the one which is glaringly obvious. How sensitive are they? Those green ones are 25miu aren't they? So if these are more sensitive and your pee was very concentrated with the obvious test then I would still say try another, equally concentrated sample with the same brand and look in the timeframe then after an hour and see if any changes happen. Some will show a faint line which darkens over time but this isn't an evap, an evap won't be coloured usually. Most of the time they're grey/colourless. Tests require the hormone to turn them pink, it's a chemical reaction which causes the colour to be there, rather than time. Unless it's a wonky test, which does happen sometimes. But the amount of times you have tested, and I'm pretty sure I recall you using these tests before, you haven't had a line like this until now. So I would have thought the chances of it being an evap are slim when you take into account all the other tests you have used over the months