One group I would add to you group of government idiots is DCAA (formerly DCAS).
We were delivering shelters painted with mil spec paint supplied by the government and they squawked that it wasn't the right lustre. They refused to sign the DD 250 until we stripped and repainted the shelters with a different batch number of the same paint.
They insisted we pay for the rework under threat of a "Method C" which would have implied that we had serious systemic QA problems.
Years later we finally were awarded consideration because an arbitrator declared their action was a constructive change to the contract. The dufuses that perpatrated this went on to higher positions because of their "diligence".
Guess who paid the bill? The taxpayer of course.
I’m glad there is someone else here that knows the deal. Too many here are quick to blame the contractor, yet they have no clue how the process works.