The B787 was due to run from Sunday just gone to tomorrow. However every day it has changed to an A330, or, in today's case, a B77W. Thursday also sees 2 B77W.
It could be a case that the flights have been too busy to effectively 'downgrade to a B787.
It's suggested that one of the flights will change to a B77W and the other stay an A330. It could still likely happen.
In terms of being disappointed in terms of MAN remaining A330 over the B787, I fail to see how it would be such a disappointment.
The A330's hold more cargo, have a higher passenger capacity, have been refitted to the latest Qatar interior and, based on current reviews, the A330 seems to be more comfortable than the B787 as the Boeing is described as cramped and narrow compared to the A330.
Personally, I'd be disappointed if MAN was downgraded to the B787, especially given the larger B77W needs to be fostered on more flights at the moment.