Outlook appends attachment file names?? (adds [1][1]…)

Hi there!

Using Outlook 2011 for Mac and one thing that is driving me a little bananas that I am not sure how to fix is that if I click and drag an attachment from one email into another, it --oftentimes-- appends the file name of that attachment by adding numbers onto the end of it...

Does anyone know how I might fix this?  I went through all of Outlook's preferences and all of my system preferences, as well. I believe it's related to the Outlook Temp folder.  Is there a way to change the settings on the temp folder such that when you drag a file from one email onto another that it doesn't treat it as a brand new file (thus having to re-name it so that there aren't two files with the same exact name in the folder itself)?  Hopefully that makes sense... here's a screen-cap of my temp folder to kind of help show what's happening:

Thanks!