What I did:
Created a note.
Update didn’t change the date, move it to the top. ( Most recent date)
What I expected:
Update to move note to the top.
What I did.
Manually moved not to the top. Time consuming with a folder full of notes and updates.
Work around, create updates as new notes.
Not as efficient as updates are tied to originals via content and context.
Things that might be helpful to know (Agenda version, OS and model, etc):
The error message you got suggested you tried to move the note to a place where it would leave the date order of all notes in the project in an inconsistent state, i.e. no longer in (reverse) chronological order, which is something we require to always be the case. It therefore also depends a bit on the sort setting you have chosen for the project (that you can change when tapping/clicking the title of the project at the top of the screen).
If you assign a date to a note that hasn’t got one, like in your movie after you were forced to remove it, you will see it move to location where it would chronologically fit if needed. So that’s the first thing I’d try, where does it go in that case?
Second, if it then moves it away from the top but you’d still would like it to show at the top, the answer could be to either change the sort order (from say chronological or on title to reverse chronological), or alternatively you can pin a note to the top by clicking/tapping the dot icon left of the title in the upper left corner of the note. Pinning will allow you to override the sort order and make a note always stay at the top. Which can come in handy for notes that are currently your priority/focus for example. Unpinning when you’re done with them will then make them return to their logical (chronological) position.
Hope that helps!