The big city drop wasn’t particularly late. The individual precincts get reported very fast after the polls close at 6 pm, and are known to both sides and then the aggregate gets to the media and networks when it usually does, about 730. That put Beshear around 30,000 ahead. The later votes were especially from the Western part of the state (a time zone later), but also from some VERY strong GOP counties (Russell, Laurel, etc) which cut that down and almost caught Bevin up (he is down about 5,000). It was more the reverse, with some GOP areas coming in late and almost pulling Bevin through.
The FINAL Louisville numbers were very late. Both Lou and Lex published significant data relatively early. But, Louisville held about 25% of theirs until the VERY end.
It was suspicious timing.