I don’t know if this kind of thing is captured very well but I wonder how many voted blue for other Federal offices but simply skipped President.

Trump won PA by 144,739 votes, but Casey is only trailing McKormick by around 40,000 votes, which may get narrower as all the ballots are counted. So I’d rate this plausible.

Edit: In the other statewide races the democrats lost by even more than Harris did, so I’m not rating this plausible.