It would be nice if nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z can clarify how timestamping works. But my guess is that it is linked to a note not edit. It would be better if one could timestamp each individual edit as separate notes and as one switches between edits one can see if they are timestamped or not.