this has happened before, so I tried to be careful, but I wasn't careful enough.
Logos says I have 116,000 notes including highlights
So a given verse may have two, three notes plus highlighting.
I had a verse where one word seemed to be in bold.
I didn't see why I might have done that, so I thought I would undo that. I highlighted the word, and the menu showed me I could delete it.
I did and two real notes disappeared too.
And those notes didn't appear in the trash or undo with Control-Z.
So I have no idea what was in the notes I lost and no way to get them back.
So it seems if I have highlighted something, I should just leave them alone. Never undo a highlight unless there is nothing around anywhere close