Today I had a look at Sharing Documents and List Items in modern lists and libraries in SharePoint online following a post on Tech Community. Recently the interface for this has changed and When you share a document you get a dialog like this:
When I share a list item however I get:
Notice the difference! The option to share with your organisation seems to be disabled for list items but not for documents.
The odd thing is that apparently my organisation is preventing me from selecting this option. I’m not aware of any setting that can be made related to Sharing that is just for lists or libraries only.