Here's the scenario:

Office XP, Outlook integrated with iManage, sporadic unpredictable problem. User attaches a Word document and either a Visio file or PDF to an email (which is not necessarily to say it couldn't happen with other types of files, but we've only seen it with these two). When it is sent -- and it doesn't matter if it's internal or external -- the Visio or PDF is deleted from the email and replaced with a Word document with the exact same name as the one attached. It has identical contents as well. The only difference is that copy always comes out to be roughly 3kb smaller than the original. It does not only appear this way for the recipient; the user can go to his Sent items and see that this is the case.

Any ideas why this would happen?

By the way, this also occurs with local documents not just docs pulled from the iManage database. But iManage is still integrated with Outlook so perhaps its somehow part of the equation in the background.

This occurs with emails sent within our network and with outside email addresses.