Other relevant info…. on desktop, I just created an item, pasted in a note, looked at the item in mobile and found it had a caret next to it as if it had a subitem (it did not and when I tapped the caret it did not reveal any subitems). When I opened the note window for the item on mobile, the notes were empty. Checking back on desktop, the notes on the item were empty.
It’s as if the newly created note is being treated like a sub item on mobile, and thus the item has no note. And it seems that when I select it for editing and go into the note editor, the empty note gets synced back to desktop and overwrites it? Just a guess.