This happened in 1.14 and I have not confirmed the error in 1.15.
The South had a Victory Point lead of 4862 to the Union 2197 but there was no National Morale victory possible (CSA 80 vs USA 98). The Union player was host for the game. At the end of turn 115 his game reported a Stalemate (both on screen and message log). When I received the game TRN file and ran it it displayed a CSA Victory (also in message log).
Seems there is a little problem here.
I have attached screen shots of the bottom of the victory screen.