RetiredF4, this needs definition, "at or close to the maximum recommended FL".
Some discussion here has suggested it was not particularly near maximum recommended FL and had a considerable speed margin both above and below the speed at which they were operating. So in context I wonder what "close" would mean.
If it was "close" and the stall warnings were transient, that suggests the PF should have done nothing for long enough to see if the warning would go away. Near the ground an instant reaction is needed. At 35000' it seems there is a lot of time to spend thinking before action becomes critical. And it would take you out of any transient condition that would suggest stall.