As of the time of writing (around 11 pm Central Time on Nov 6,) there are currently still 3 races for seats in the U.S. House of Representatives from Pennsylvania for which the Associated Press has not called a winner. Specifically, districts 7, 8, and 10 aren't called yet. However, in all 3 of these, the AP is estimating that 99% of votes have been counted and one candidate is ahead by 1.4 to 2.0 percentage points, which seems to suggest that it is now mathematically impossible for the leading candidate to not win the race. The percentage of votes counted has been showing numbers that suggest impossibility or near impossibility of the race going the other way almost all day today.
Similarly, North Carolina's district 1 also isn't called yet, despite AP estimating 99% of votes counted with one candidate having a 1.8 percentage point lead.
Is there something special about Pennsylvania elections and/or North Carolina for U.S. House seats that I'm missing for why AP seems to be holding off so long on calling them when their own numbers seem to suggest that the result is certain?
Do they have an automatic runoff or ranked-choice voting or some such thing that would cause the AP to wait longer than usual to call the races? Or does their Decision Desk think there are more votes left to count than their numbers seem to suggest? Or some other reason?
In NC's case, no candidate is above 50%, so an automatic runoff or RCV might explain the situation if they have that, though in PA's case, all 3 of the races have one candidate well above 50%.
I looked at a lot of AP's Election Updates page, but I haven't seen anything addressing these House races (whereas they have released statements there explaining why they haven't called certain Senate and Presidential races.) There are a lot of updates there, though, so it's possible I missed something. Obviously, direct statements from AP would make a great answer to this question if I've just missed them.