Calendar not saving event note edits

My personal calendar on macbook is not saving event note edits. If I open an event on my personal calendar and make an edit to the notes about that event (which is often where I keep important info about the meeting), frequently the revised notes are gone and it has reverted back to the old notes. My calendar is synced to icloud and the behavior appears on both macbook and icloud (and iphone). This has created many problems where I have lost vital info that I can't retrieve. It just started to happen in the last month or so.