This appears to be down to some delay in saving the note content after input stops… I don’t know if this only occurs when deleting the whole note, but that’s the simplest way to get it to happen.
I think this probably happens for newly created notes only — or, out of curiosity, can you reproduce this also for notes which had already existed when activating them in the notepad (i.e., if you create a note then select a different note or item and return to the previous note)?
The notepad is definitely not ready for this level of scrutiny