My understanding of married segments does not explain this.
Married segments means that inventory on A-(B)-C might not be available on A-B and B-C, or vice versa.
But one can always book A-B B-C with a fare break at the summed price of the two legs.
As such, the OP was just a victim of brain dead service.
Can any of the routing guru's clarify if my understanding is correct?