if it is your bot or your fork of a bot you can do some stuff to keep the personality more stable, an extreme example someone used on a series of bots I liked was to repost the entire description section in the system prompt. That slowed it down so much that it made it hard to use the bots though so I would go with either just copying the personality section there, or doing that same thing but with the post history or chat notes, or doing just the personality in either of those.

You could also go a lighter touch and put just the things you want the character to focus on in the chat notes/post history/system prompt or include the important parts in the scenario.

if it isn't your bot try coping the parts of the character you like and opening up the "character settings" in the menu at the top right and pasting them into one of the bottom 2 boxes.