During the 2008 financial crisis both Obama and McCain had White House meetings to try and figure out a solution, that was before the election. But I guess in that instance they were all basically on the same team and Bush didn't want to set up his successor for failure, whomever it was (McCain would've probably done the exact same thing).
I mean, I don't. He was terrible and I hate that Democrats are laundering his and the Cheney's reputations. It's just that Republicans have always been on a downhill trajectory, each President worse than their predecessor.
But, eh, he's been meeting with World Leaders™️through out Biden's term, and that's really not normal either. (well. with the exception of the sitting president asking an ex pres to do some negotiating or something. That kinda happens.)