At a current client I am seeing this scenario play out often:
1) User clicks on an Office document in a SPO document library, and it opens in a new tab in the associated Office Online app. They make an edit, the edit is auto-saved, and close the new tab. Or, they don't need to make any edits, just needed to view, so they close the tab.
2) In the original tab, they attempt to add metadata, or delete the file, but are told the file is locked. It then needs to time out before anyone can make edits to the file, and there doesn't appear to be any way to release the lock manually.
The file would not be locked if the user refreshed the document library page after closing the additional tab, but this is not realistic to expect the user to know to do to avoid locks.
I would like such documents to open in the same tab so the user would have to trigger a refresh when returning to the library. As far as I can tell this is not an option in settings - is this true? Is Microsoft aware of this bug? It is causing untold issues.
