OK, I was playing around and I figured it out
I entered the 24th and it was correct saying that it was 3 days away
Then, I entered the 23rd and it said that it was one day away, even though it should say 2 days.
When I entered the 22nd, it said that my event has arrived instead of saying that it was only one day away.
So, when you get down to 2 days, it skips a day.