I started using two factor auth because of this thread -- it was suggested a while back as a possible "solution".
I'm starting to notice the Reconnect email comes upon using different Windows devices. I've ignored this thread for a while but came now because I just had to authenticate to Google on a Surface and immediately got the email afterward. Previously, I got
an email when I opened a Windows 8 calendar app, which can't be hooked up to a Google account but I have shared calendars with my MS account so Google calendars are viewable. Before that, another instance was when I upgraded to WP8.1 on my Lumia. So I'm seeing
a pattern of a device/app triggering the email when there's an MS/Google handshake.
Aside from the two factor suggestion, I haven't heard much in terms of possible solutions but I also haven't heard much in terms of symptoms/triggers either. To me, perhaps that is what can be investigated? Perhaps that's what's really going on in the private
messages?