If you have done something wrong. Something is coming in late. A mishap has occurred that was mostly out of your control but for something you are responsible for? A misunderstanding has arisen.
It isn't a sign of "weakness". It is a sign you are taking ownership and responsibility for the part you play.
It isn't a sign that you "lost" and someone else "won". It is a sign that you are still ready to learn. It is a sign you are ok with taking responsibility.