I can't let this thread go with adding my own howls of complaint and frustration, as it wastes my time, wastes dc's time and makes *A look bad, but I shall continue to pursue the matter.

I have no idea (how could I?) but I would suspect the issue lies with how much CO wants to compensate BD. (My CO ticketed/UA metal codeshare flights posted straight away.)

But it's really a very poor show indeed.