Problem-solution firewall
In his book Clear Thinking, Shane Parrish explains how to avoid finding the perfect solution to the wrong problem
have two meetings: one to define the problem and another to find the solution(s)
At least to me, it seems immediately apparent how a well conducted post-mortem facilitates exactly that.
In the first phase we gather the data, establish facts and timeline. Once that is written down (emphasis on written!) we can start exploring solutions to prevent, detect and/or mitigate.
At the same time, what we're achieving is slowification (i.e.: taking work outside of the normal flow and make time to analyze it), which is another critical step towards continuous improvement.
It's a simple process, but not an easy one.