Is there a kind aphorism for someone who has made a mistake, been forgiven, but shouldn't be given responsibility?

I'm trying to explain a situation where a person has made a mistake. They have made up for their mistake. They have been forgiven. The wise boundary is not to give them responsibility for the area in which they made a mistake.

I've come up with a few examples that don't quite work:

Putting the chocolate thief in charge of the lolly jar

This is snappy, but thief implies larceny which isn't appropriate.

Putting the fox in charge of the henhouse.

This is the classic one. Fox implies a defective character which is mean and isn't the case here.

Putting the person who dropped the Ming Vase in charge of the China Shop.

This is kind, and almost works because dropping something is a mistake. But it isn't snappy.

My question is: Is there a kind aphorism for someone who has made a mistake, been forgiven, but shouldn't be given responsibility?

"Forgiven but not forgotten. "