I keep forgetting to say this (and also thinking it's too late). 343i could I ask you for something? It's something you can do without needing to change the engine or issue an update or anything like that. Could you put some kind of versioning on maps in matchmaking? Something in the name or the description? Some of them have had it but only ones I'm sure were community maps where the creator did it themselves.
(also I don't mean for this to sound patronizing or to sound like begging, just a polite request)