He didn't get a penalty for it, which is absolutely nuts - the penalties were co-incidental roughing minors between Backes and Polak, there was nothing for the elbow.
However, it's not suspension worthy in the playoffs. I think it was a purposeful elbow made to look possibly-accidental, but it's hard to know that for sure, it could have been fully accidental. More importantly, Andersen wasn't hurt on the play - for something to generate a suspension in the playoffs, it either has to be SUPER blatantly awful, or it has to cause an injury, that's just how the NHL seems to dole out suspensions. This is maybe a 1-game suspension in the regular season, but probably either nothing or a fine, in the playoffs plays like this (if they don't result in injury) are generally no discipline at all.
I could care less about the suspension, but I would like to see more consistent calls in game. The reffing has been crazy inconsistent this series, within games and especially between games, massive variance on what's a penalty and what isn't. This should very clearly have been a penalty. You even see the one ref immediately put his arm up to call it, but the elbowing penalty mysteriously disappeared after they sorted out the co-incidental roughings :/ Just call the game by the rules! Don't be like "oh, there was a fight, so we need to make sure everything's balanced and there's no PP, because playoffs."