SkyDrive group email causes duplicates

Hi all,

I'm here to post about the following issue I posted last year:

http://answers.microsoft.com/en-us/windowslive/forum/sync/skydrive-groups-group-email-causes-duplicate/37f85ce2-db6f-473e-b708-f377ba468140

However, I have made my own investigations:

First off, the duplicate emails do not appear in the Outlook.com web interface. It only appears in email clients - Windows Phone, Windows 8 Mail app, Windows Live Mail, etc. I downloaded and installed Windows Live Mail from the Live Essentials pack and used that to extract the message source of the duplicated emails.

As the emails probably have some identifying information (mainly email addresses), I will wait for a forum moderator to privately post information.

I have a hypothesis that it might be due to having email forwarding enabled, and somehow because of the way group emails show who the email is from, it's appearing twice in my mailbox? My primary address is an Outlook.com account, with all mail being forwarded to a Gmail account (for backup), however, one of the two duplicate emails contains Gmail information, including some Gmail authentication keys. (Note: I do not know how to read email headers.)

Thank you in advance for your help!