Help please??

Okay so I know your not meant to look at test past the 3 minute mark so I know this test is invalid. I took this test about 5pm and thought I could see something very very faint but just left it as I assumed it was negative. When I looked back 4 hours later I could see a line but I know it's most likely an evap/indent line because of the timeframe. But has anyone experienced this? I'm only asking because I've taken A LOT of FRERs over the past year and I can't recall seeing any line even when I looked back. Just looking for anyone who has experienced this? Thanks!