When the local record button, aka "Per Property Recording" is selected, it does not record changes of that property. No matter if the changes happen in the form editor or the Property editor.
Edit: This is a currently known issue. Per property (aka "local") recording does in the current state only work when modifying the property in the line edits right to the record buttons, but not when using form editor or property editor. Fixing this for the 1.0 release is unlikely. So we either hide the local record buttons, or add this to the known issues list.