faint lines on a HPT after allotted 10 minutes

Hello. I realize that HPTs are not intended to be read after the allotted 10 minute test time. However, I have taken several in the past and gone back to check them later, in hopes that there might be a positive result..sometimes hours, or days later..there has never been anything but a negative result...
However, recently I had implantation bleeding on the 13 and 14 of August and began thinking I might be pregnant. (The last time I had sex was around the 4th of August) I am on a pretty regular 28 day cycle...My period is not due until August 23, but I think I may have ovulated early this month, and thought it might not be too early to take a pregnancy test.
SO, 2 days ago, I began taking one every morning. The first one was negative, but showed a faint pink line about 6 hours later...I thought this was odd, since that had never happened to me before.
Then, the next morning, the HPT was negative, but showed a faint pink line about 4-5 hours later,
Then this morning, I took another negative test, but it showed the pink line only 1.5 hours later.

Could this just be coincindence, or is it possible that I am testing a bit too early and the tests are showing low doses of the pregnancy hormone? I have read about evaporation lines, but I heard they are colorless...wouldn't I have to have the pregnancy hormone in my body to test positive on a HPT?

Is it possible that the pregnancy hormone is increasing daily and that is why it is taking less and less time for it to show on the HPT? I do realize these tests say they are only effective during the 10 minute time, but could that just be a disclaimer?

Any information would be greatly appreciated...I am very anxious to find out if I could be pregnant or not. Thanks!

It could be that you have very low levels of pregnancy hormone, but the tests are unreliable that long after they have been taken. My advice is to wait a few days and test again.

welll not that im a scientist or anything but that would make total sense to me. i wouldnt have the time or patience to do the timing and everyday.... wow. but being a poas aholic myself i totally get it. lol. now that would help me out too. i had a 3 pack of walmart brand tests. took one around ovulation time, knowing it would be neg. kept it for 24 hrs to watch for "evaps". nothing. took one thismorning and if any lines showed they wernt dark enough to tell, but then all of the sudden 20- 30 min later a totally obvious pos was totally there! cycle day 21 today but not sure when i ovulated. usually anywhere from 29-32 day cycles for me.