I did one not too long ago about this.
All point are based on a 24 hour period. So if you visit so 6:03 pm then you will not get a new visit til that 6:03 pm the next day.
I showed a similar examples of where it missed a day or two where it did not give your points for visiting for a day or two. Even though I thought I was on there after the yesterday time. I think it was maybe a few months ago that I reported it.
Anyways I agree that it is an issue but have not analyzed the issue yet.
My initial thought ( which I did not test yet) is that it may be looking at the time instead of the 24 hour total. Say I am on at 603 pmon day 1, day 2 did not get on but day 3 I may have got on at 4:04 and it did not give point til I came back at 6:10.