Interesting to read your ability to manufacture the routing to get you to DEL, however circuitous.

I had a similar issue come up with ORD-HEL-CPH on AY. Both legs available on AA and BA and EF, and the original reservation came back with confirmed legs and segment numbers and all. That confirmed reservation was put on hold. When we went back to ticket a day later the ORD-HEL was unconfirmed. No work by the agent was able to free it back up.

I wonder if it's possible to ticket the obscure itinerary involving another partner and then go back and see if changing to the original, desired itinerary would work?

Thankfully the agent was a backup supervisor and able to rebook the entire itinerary in J on mostly AA metal.