I've been trying to test out the Edit in Office functionality for attachments and encountered a bit of a roadblock. Basically, everything works exactly as anticipated for Word documents, with a new version uploaded for each saved edit. However, I'm unable to upload the edits at all for Powerpoints and Excel files.
For each, I initially enable editing, but then receive this error when I try to save the edits to the server:

When I re-open the document after this, it tells me that "someone updated the server copy and it's not possible to upload your changes now." However, the Confluence version remains the same. Has anyone else experienced this?
Technical specs:
Windows 10, Office 2016, Google Chrome v62