".tmp.driveupload"

I am having an issue where my word doc (set to autosave to OneDrive business desktop app) on my PC is suddenly saved in a ".tmp.driveupload" folder online under a different file name (random numbers), with autosave switched off. 

If I do not notice this happening, the change to the document is not saved under the expected folder and file name, resulting in no change made to the file I opened. 

The only workaround I've found is to "save a copy" and overwrite the file I opened in the original folder. This only works if I notice the sudden name change and file save in the tmp folder. If I don't, the changes are lost because the tmp file is deleted (to recycle bin) on exit and the tmp folder is not synced to my PC. I have to go online to the OneDrive business website, guess which file it may be, restore that from the OneDrive recycle bin, and hope it is the file I was looking for. The frequency of this happening means that there are numerous tmp files under pseudo file names to scour through. 

One-hour plus on the phone with MS Office subscription support is of no help.