Keynote’s Presenter Notes Repeats (same) across all slides

Keynote:

version 12.1 (7034.0.86)

MacOS

Big Sur v11.7.2

MacBook Pro

Retina, 15-inch, late 2013

Problem » Keynote

Adding/Editing Presenter’s Note in one slide changes all slides. Thus, all slides share the same Presenter’s Note uniformly.

Each slide cannot have its own unique Presenter’s Notes that expresses for that slide alone.

Please help urgently.

1. Advise what can we do to revert back to independent slide’s own Presenter’s Notes.
2. If it is a bug, please rectify ASAP.

Unless it is changed, Presenter’s Notes is not useful at all.

p/s: read past Support Notes but found no answer to rectify this.