Apple Notes - Shared folder not syncing between macos versions

I have a new M2 Macbook and an old mit 2012 intel-mac.

I am not able to add the old mac (macos catalina) to my apple id anymore so I am using a shared apple notes folder to keep my notes in sync. I created a subfolder in the shared folder on my old macbook but it does not show up in my notes on the new mac. BUT when I search for the folder name all my notes from this folder show up. How is that possible? am I doing something wrong?