OneDrive iOS - not showing all files in shared folders (related to shortcuts)

We have a major issue where the OneDrive iOS app does not show all the files in folders which have been shared with the user e.g. from SharePoint. This only happens when an individual folder has been shared with a user, and the user clicks 'add shortcut to my files' using OneDrive online. Symptoms:

- They may see anything i.e. it shows as empty when it is not.

- Or a few files or folders

- Or all files, but then new files added later don't show.

The folders have been shared from Teams/SharePoint using the share button, and shared directly with the user. If the user then adds a shortcut, or clicks Shared in the OneDrive app and opens from there, the result is the same. Different iOS devices show different files, so it's nothing to do with permissions.

The app is up to date, as is iOS (iOS 14.4, app version 12.18.8).

So this is the contents of the Board papers folder, which has been shared with me. I can see all the files and subfolders in Windows or web:

Now, on 2 different iPhones, they both show just one item:

Needless to say I am signed in to both phones, and web/PC with the same account.

Also, the new Office app doesn't show the shortcut at all in OneDrive, although can be seen in Recent Folders, and in fact shows all the files in there. But recent folders is not reliable e.g. a folder someone is looking for may not be there.

This issue is affecting multiple users and easily reproduced. Clearing the cache does nothing, signing out of the account and back in sometimes makes different files or folders appear, again not all of them.