So, although this is now available, it does not seem to be working correctly.
I know my audience quite well from GA stats and UTM captured campaign stats, favouring 63%+ mobile devices. However, the device and operating system stats I see here in MW shows 95% Windows / 97% Desktop / 80% Firefox Browser. That's just completely impossible. Yet, it's consistent through all campaigns. It can't be me, because I don't use Firefox.
Am I missing something? Does anyone else have that same problem?