A mistake needs correction and a clear account of what allowed it to happen. It should not become a permanent verdict on the person who made it.
After an incident, distinguish the recovery from the review. Establish whether the immediate problem is handled, then examine the decisions, controls and conditions that produced it. Keeping those questions concrete makes it easier for people to report the next problem early.
A retrospective can drift into a discussion of character. That drift leaves a team with a story about who failed instead of a useful change to the system. Keep the review tied to the behavior, its consequences and the control that should prevent a repeat.
Holding someone to the same standard after a correction is demanding enough. Raising that standard for months because of one past mistake teaches people that admitting a failure creates a debt they cannot discharge.
Psychological safety can coexist with high standards. People still need to correct their work and take responsibility. They also need to know what a completed correction means.
When the fix and the learning are in place, let the next piece of work be judged on its own evidence. A team that expects its last mistake to define every future decision has a reason to hide the next one.