A Microsoft file hosting and synchronization service.
Hi Rory,
Thanks for sharing updates with us.
If you see a "people" icon next to your OneDrive files or folders, this indicates the file or folder has been shared with other people. I have tested from my side when I share a sub folder within main folder the people icon only shows in sub folder not in main folder. See image below for your reference:
Since, issue only happen to one folder I suggest you please open your OneDrive online and right- click on problematic folder >click on Manage access> remove the share link and then again share a sub folder and see the result in main folder does still you see people icon on main folder.
I appreciate your patience and understanding.
Best Regards
Waqas Muhammad