iCloud Notes syncing issues - "You have changes that can’t be uploaded."

In August 2018 I created a note and shared it with several other users. It was used for a couple days then never opened again. In early October 2019 I updated my iPhone to iOS13 and every time I opened the notes app I would get a pop up saying "Changes you made to “[name of note]” can’t be uploaded since the owner’s iCloud storage is full. Your changes are saved on this device and will be uploaded once the owner creates space." I created the note. My iCloud storage is not full (I'm on a family plan with 67/200 GB used). I deleted the note but I continued to get the pop-up. The note does not even exist in Recently Deleted anymore. I recently updated my Mac to Catalina and now the desktop Notes app has started displaying the same pop-up. As a very frequent user of Notes, this is super frustrating. Has anyone else dealt with this problem?