Upgraded to Outlook 2013, also on latest X1 8.3.2.1 (build 5003eb 64 bit) and now I see duplicate entries for emails stored in Public Folders, with the duplicate being in the path of /Recoverable Items/Deletions path.
I did a complete re-index and these went away, but over time, they come back. And, it's not for all emails, but it is for many.
The PC that this is showing on was fine with Outlook 2010 installed on it - so, I think it's the introduction of Outlook 2013. Note, this PC is not the one that is moving emails around - it is used just for indexing of X1. Note, other PCs with older X1 and Outlook 2010 are just fine - with no changes seen at all. That is, these other PCs don't see this recoverable items path duplicate emails at all.
I did a complete re-index and these went away, but over time, they come back. And, it's not for all emails, but it is for many.
The PC that this is showing on was fine with Outlook 2010 installed on it - so, I think it's the introduction of Outlook 2013. Note, this PC is not the one that is moving emails around - it is used just for indexing of X1. Note, other PCs with older X1 and Outlook 2010 are just fine - with no changes seen at all. That is, these other PCs don't see this recoverable items path duplicate emails at all.