Further to what @mwra mentions, if you want to revert the key attributes for a note to the prototype's KA (i.e., override the local note settings that Mark discussed) there are a few ways. You could use a stamp, an agent, or simply open Quickstamp and click the button under "default". If there is a prototype assigned to that note, this action will revert the KA for that note to the prototype's KAs
No bug. This is just the way inheritance works.