Hi Chris,
We do have some progress regarding this issue. We found that the incident occurs when the tenant is upgraded to SharePoint 2013 but remaining in SharePoint 2010 mode. We are still working on it to come up with a long-term solution.
In addition, we could also provide you wit a workaround currently. Please refer to the following workaround for detailed explanation:
- Option 1: Open the show unique permission page directly
https://<Your tenant>.sharepoint.com/_layouts/uniqperm.aspx
- Option 2: Open the show unique permission page directly
Replace the user.aspx in the url to uniqperm.aspx if the url had query parameters like "?obj=". For example:
We could change https://<Your tenant>.sharepoint.com/_layouts/user.aspx?obj=%7B0
to https://<Your tenant>.sharepoint.com/_layouts/uniqperm.aspx?obj=%7B0
Please let me know if you have any concern.
Regards,
Allan