If the CRA continues to show the CO or colection in any credit report they issue after that exclusion date, personally, I would not file a dispute.
A dispute will result in a dispute flag being posted to your CR, which messes up scoring until removed. CRAs are notorious for not deleting dispute flags after resolution of a dispute, so you could be creating another hassle.
I would recommend handling by way of a formal complaint sent to the CRA of their violation of FCRA 605(c).
If that bears no fruit, send the same complaint to the CFPB.