Airbus had a backlog of 75 A350-1000s but its latest order and delivery figures show Etihad's backlog of 25 has been cut to 19.
While Etihad has not commented on the A350-1000 redesign, a source close to the carrier said it was not content with the changes made to the twinjet, echoing the feelings expressed by Emirates and Qatar Airways.
Airbus chief Tom Enders indicated there might be "short-term" issues regarding discussions with existing customers for the A350-1000.
The A350 programme secured orders for only 10 aircraft in 2011, while cancellation of 41 left the type in negative net figures for the year.
Cancellation of a single A350-800 also helped to reduce the A350 order backlog to 555 aircraft, comprising 118 -800s, 368 -900s and 19 -1000s.
Enders reiterated the airframer's caution over A350 development, admitting that postponement of its entry to the final assembly line had been decided after the programme "ran into some serious problems" with key elements.
He said the A350's final assembly would begin in March 2012. Without caution, and assurance of maturity, he said, "you're setting yourself up for disaster".
Chief operating officer for customers John Leahy said he was in discussions with three major airlines for the A350-1000, and added that the main problem was "getting them early delivery positions".