1 Positive test and 1 negative test

This morning I took a pregnancy test and it looked negative to me BUT possibly a slight positive line. Very very difficult to see. So i went and bought a digital test and when i got back home about 30-45 mins later the line on the first test was DEFINITELY a positive line now, even though still not very dark. But i went ahead and took the digital test just to be sure and it read “not pregnant”. Does the first test sitting too long create a false positive? Or is the digital one wrong? Some background: weve been ttc for 6 months now after having iud in place for 6 years. Im 4 days late but have had irregular periods so that doesn’t necessarily mean anything. Just trying to get some opinions on the matter.

Thanks!