Re: notes added to a reference keep disappearing

I am running Endnote X9.3.3 on a Mac (Sonomo 14.7) and I keep having a problem with certain references (not all) where I add notes to the reference and those notes then disappear. At first I just assumed I had made a mistake and not save the notes. But even when I save actively, close the reference, close Endnote, re-open to use the notes in the reference, and they have disappeared again. k

Any thoughts on what might be going on ?

This might be a problem with compatibility – Clarivate says:

EndNote 21 is compatible with macOS Sonoma and no major compatibility issues were found. EndNote 20 and earlier were not designed for Sonoma .