The short answer
The practitioner who vetted the engineer stays attached to the placement and raises a problem before you have to. When a placement is wrong, Conntal says so first and replaces the engineer within a defined replacement window, rather than defending the original choice or turning it into a dispute.
The engineer who vetted the placement does not disappear once the engagement starts. They stay attached to it, and in contact with the placed engineer.
That matters because the most expensive placements are not the ones that fail loudly. They are the ones that quietly stop working while nobody escalates. A vetting practitioner who still owns the placement is positioned to notice that early, and to raise it before you have to.
When a placement is wrong, the commitment is to say so first and replace the engineer, rather than defend the original decision. There is a defined replacement window, so the conversation is about the replacement rather than about whether one is owed.