Offices documents are in reality zip files with document extension. It seem Fences try to litteraly open it "as a folder" when they are open in folder portal. I notice it's append especialy when theses file has been downloaded (and have the security popup before open it)
After that, Explorer crashe .... in loop... until you rename the file.

You should fix it, docx & cie need to be oppenable as "normal files"
You should also add an option that "disable folder browsing" inside the fence portal itself but open folder "as new windows" when you trying to double click on it. Currently, folders in portal just won't have any effect if "folder browsing" is disabled in portal.