She was sitting in the "friends and wives" area of the arena, cleverly named since it is reserved for the friends and wives of the players. In the section with Cuthbert was April Reimer, wife of Maple Leafs goalie James Reimer.
Boston won the game, 4-3, with Reimer giving up the game-winning goal in overtime. Video of the friends and wives box showed Cuthbert apparently rolling her eyes at April Reimer, which many on the Internet took as a sign of displeasure. Because what's the fun of the Internet if you can't jump to conclusions based on a short video?
Well, Reimer took to Twitter later to say people misinterpreted:
Thank goodness that's settled. Now we can all sleep better tonight.