Files and folders are invisible

I have a vault (probably 8 years old) stored in iCloud and sync it to different devices. Windows, iOS and Mac OS. On Windows and iOS I can use the vault without any problems. For a few months now, the data and folders stored in the vault are no longer displayed in full on MacOS. Entire folders are empty and newly added files are also invisible. On other systems, the contents of the vault are displayed to me in full. What can I do so that I can see the contents of the vault completely again?

Thank you very much for your help!!!