Or as mentioned by one comment above, it could be the take-off performance in hot conditions.
However, if it is the case the issue should have been raised in the beginning. After all the take-off performance is in the flight manual of the aircraft (the Performance part of the flight manual, usually in the form of a software and dataset).
In addition, usually performance shortfall is compensated by the remedies as function of the estimated profit reduction.
It seems to me this is the most likely true issue, same as it probably is/was for STC and EK on T900.
I doubt the remedies cover the entire impact to the airlines, i.e. the time to remove the engine, get it rebuilt, then re-installed while a spare is fitted.
It could very well be that the cost of providing the stated durability is more than just paying the penalties so that's what the vendor does, and this angers both STC and AAB.
In particular we know the TXWB-97 is mostly a throttle push of the TXWB-84, with some flow enhancement. Maybe it is not meeting durability targets?
In this case, AAB mentioned a kind of industrial risk. Or perhaps he meant that if he cancels the remaining A350-1000 it would become an industrial issue for Airbus.
His statement was so vague that we cannot make any clear guess. This said, the way he said it sounds like the issue is relatively serious.
Or maybe he knows he has to escalate the verbiage to get attention after crying wolf so often.
Qatar just cannot be short on cash. They have natural gas like there is no tomorrow. It must be something more technical or contractual.
You're confusing Qatar the country and Qatar the airline. Even if the airline is heavily govt subsidized (denied!) there has to be a transfer of cash or a credit facility.
I don't think this is a problem. They already have gotten $3B for covid relief, if more is needed then it will happen. As far as the nation is concerned, QR is too big to fail.