Can't overrides can.
But what about "MUST" ,i think the Jap army rules say "must ignore the 1st flag"
The FAQ is clear about this. P.3:
Q. If a Unit with a Heroic Leader is behind Sandbags, may that unit ignore two Flags thrown against it in a single battle?
A. Yes, this unit could ignore the 1st Flag because of the Sandbag (Terrain Protection) and the 2nd Flag because of Heroic Leader (Special Unit Protection). This same effect would also apply to Italian Artillery Units and Imperial Japanese units. However, if attacked by a Barrage or Airpower card, the unit would not be able to ignore any Flag because those cards always overpower the protections.
This comes from an original post on the Memoir '44 Forum:
RBorg wrote on Wed, 12 April 2006 10:57 wrote:
Q. When a Command card states "flags may not be ignored," must Japanese infantry ignored these flags?
Command cards the state flags may not be ignored still will cause Japanese infantry to retreat. Like many of you, members of my game group refer to this as ?Command cards trump the rules?.