If you’re in charge, the mistake is partly yours even when someone else made it. That’s the job.

Being responsible for a group means being responsible for what the group produces, including the parts you did not touch. Somebody was unclear on the instructions, or unsupervised, or set up to fail by the plan, and those are all yours. It is not about guilt, it is about where the fix has to come from.

When something in your group goes wrong, say what you will do differently before you say anything about anyone else. Then fix the setup, not just the instance. People follow that much harder than they follow blame.