The rule is if you get an instigator in the final 5 minutes you are suspended 1 game. However, it always gets reviewed by the league to determine if it fits the spirit of the rule as it was put in, which is basically to prevent message sending for the next game for something that happened earlier or just general mayhem the league doesn't want.
In this case, they could very well withdraw the suspension as it doesn't appear to fit either criteria. Although I will admit I may be a bit biased here and the criteria is very vague. However, in other instances this year with Jordin Tootoo and Matt Walker and others that have gotten the draw on the other and popped them in the face, they weren't suspended. And this is the playoffs.