Windows 10 (Win 7 and 8 work as expected - you can have many open instances of the Excel application and when you EDIT then save it works)
Chrome & DW Web Client v7
Open Excel > Blank File
EDIT Excel file in tray > file opens in Excel > Update one cell and Save, then Close
File never uploads back into DW and the update the the cell does not appear.
In IE it give an error EDITING THIS FILE TYPE IS NOT SUPPORTED IN DOCUWARE - monitoring of changes is not possible for it - the file has been updated and changes will not be uploaded.
!00% reproducable.