Board Game Arena

I was confused as to why I had a 4 player arena game of this. All my other arena games are 2 player. It seems the arena preferences do not specify how many players the game should have. I've never seen this in any other game in arena mode - is this intentional or an oversight? It also looks like I can change my own preferences for number of players in arena mode. Again, I've never seen this in arena; it's always been fixed for the entire season. I'm not a Hey! That's my fish guru, so unable to check information on that page.