I do, it's just happened to me twice in a row.
That's not the first time either.
I think it must be a bug.
Do you have your account set to no random or change settings to oppoents Because if your account is set as change your settings to your oppoents then if your opponent is set as random you will play as random. (to check go to settings and select the preferances tab).
If you do have it set to no random then it's a bug.
AA it changes based on the settings of the players in room, thus if 7 are random and 6 are no random its random.
Leave the room and come back in about 5 minutes if you need to. That or maybe send a request directly to Customer Support asking them for two separate rooms? You know... A DeathMatch Random and a DeathMatch No Random. That'd solve all the problems, and everyone would win.