Why do it the second time?

I witnessed quite a strange set of games on Wednesday, in two online events I ran. The game below was played in a junior tournament, and watching it I thought Black resigned a little early. It looks as though White is winning material after 12 ... bxc3 13.bxc3 Qxf5 14.Bxc6+ but 14. ... Qd7! forced White to give up the piece he had just won. White is still better after the simpler 14.exf5 Kd7 but isn't ahead by that much.
The weird thing was the same two players then met in another tournament a few hours later, and played exactly the same game! And I have no idea why.


Meuwteuw (1102) - kmthorikawa (928) [C41]
Live Chess Chess.com, 03.06.2020