Management documents state that clearly, deviation from accepted quality was permitted to protect schedule. Not the 737 MAX program incidentally, it was the 787.
Not unique to 787- for way too many years after Bill Allen retired, the mantra was ( is ? ) the three most important things in the factory are Schedule- and the other two dont count.
Often its ' load date' ( first load into a specific assembly jig.) Of course other variations - but the basic driving force is the same.
777 was a bit different as both Phil and Alan pushed the ' working together ' mantra in Engineering- and a reasonable amount of it trickled down to shop.