EVO 2/3 to 3/5?

Earlier today, pool play was 2/3 but then some matches ended up being 3/5. I was wondering what actually happened, because it seems unfair to switch it up after the tournament starts. Can someone shed some light on this.

I thought it’d differ from game to game. Like UMvC3 would be 3/5 but melee would be 2/5

Check the rule set for your tournament. Many tournaments make standard matches 2/3, with all Finals matches being 3/5.