Does it also happen with vaults that are located outside of OneDrive?
I’m not sure. I don’t have any outside of OneDrive.
Does it happen with all Office files? You mentioned that it’s “quite often” or is it “always”?
It happened with both .xlsx and .docx files. I haven’t tested more but I would guess it would happen with .ppt/x files as well. Always wouldn’t be quite accurate. See more details below.
Do you have a reproducable example? If yes, could give a step-by-step instruction?
Open OneDrive .xlsx file on computer A with office 2016. Edit/update file and save and close on computer A. Open the same file on computer B with Office 2016.
I had the same issue with both office 2016 and their respective windows 10 mobile apps (Excel Mobile/Word Mobile etc.)
I found rebooting computer B would fix the issue and allow me to open the file in non-read only as well as un-mounting and remounting the drive would also fix.