This option worked me for everyone.
I believe the problem is related to "Screen Refreshing" whereby Windows redraws the sync "Icon Overlays" on the desktop (little green tick marks, brown boxes, clouds etc) in the corner of Icons on the Desktop, or in the Navigation Pane in File Explorer. Related to the way File Explorer interacts with any file syncing apps (not just OneDrive) and screen refreshing.
If you go into File Explorer, select the Desktop folder and under Options/View, turn off "Show Sync Provider Notifications" and also turn off "Always Show Availability Status". This should significantly reduce the problem. The problem may still occur if you are renaming multiple files and you select part of the next filename quickly after already having renaming one. In this case the selection might still default back to the full filename once, but it won't keep re-selecting the full filename. May also occur if someone else is updating files in the same folder you're renaming files in.