Not what I'd call the most helpful response but I agree, it's most likely due to the new multi-room feature. As I understand it (and I'm not using it myself), you define a group in the app and then, when you want to stream your music (it doesn't work for radio stations, I've tried that), you tell it to do so by using the name you gave the group. If you somehow got confused and gave your group the same name as your device, then I'm guessing it would respond by directing the music to where you gave the command. I'm not entirely clear from what you said whether or not the indoor Echo streamed your wife's music outdoors and shut off the indoor one or just streamed the same to both devices. Either way, I'd say it's the multi-room thing and you maybe need to look into that to see what it's up to.