According to Catholicism, only mortal sins result in condemnation and a mortal sin requires the act to be grave matter and to have been committed with full knowledge and consent of the will.
But the negative moral precepts, those prohibiting certain concrete actions or kinds of behavior as intrinsically evil, do not allow for any legitimate exception. They do not leave room, in any morally acceptable way, for the "creativity" of any contrary determination whatsoever”. -Veritatis Splendor 67
Does "legitimate exception" mean a person is culpable regardless of full knowledge or consent and regardless of conscience?