A Microsoft file hosting and synchronization service.
I submitted this as a formal fault report to Microsoft Support and received the following response:
"Thank you for contacting OneDrive support. We hope you are doing well! We apologize for the inconvenience caused. We assure you of best assistance and anticipate your co-operation in getting this fixed.
Thank you for bringing this issue to our attention. We understand how frustrating it can be when shared folders turn into links to the website. We apologize for the inconvenience this has caused.
Our engineering team is aware of this problem and is actively working on a fix. Unfortunately, we do not have an estimated time of arrival (ETA) for when it will be resolved. In the meantime, we recommend accessing the shared folders from OneDrive for Web as a workaround.
For now, we are archiving your case. If you experience any further issues with OneDrive, please do not hesitate to write us back.
Thank you for your understanding and patience.
Have a wonderful day!"
So, they are aware and at least concede that it is a fault that they must fix ...