Playing TDM on a DM map?! It cannot be!

Something very bizarre occurred today at around 3:15pm Arizona time. 91/30 and I were about to play Assault on the TarydiumMine map, but when I arrived apparently any players that were there before had quit, since it was treating it like a game over and forcing a map vote. I decided to let it choose automatically, and didn't vote. The map chosen by the server was DM-Sympathy(ONS).

Next thing I know, we're playing TDM on the DM map Sympathy. I also noticed that no matter how many kills I got, the team scores were 0 the whole time. Eventually it crashed and reset to standard Invasion.

I'm pretty sure this is one of those "once in a blue moon" occurrences, but it was still really weird (can't say it wasn't a blast, though.) Has this happened before to anyone else?