...does this trigger the "Multiple Attacks" rule (p. 111) in which the attack dice must be divided by 2?
No, the Multiple Attacks Minor action (and by extension also Anticipation) is used when you want to make more than one attack
within the same Major Attack Action (for example by wielding a weapon in your main hand another weapon in your offhand, attacking with both weapons at the same time in the same major action).
It clear that you do not use it when making two separate attacks as two separate major actions.
It is clear that you don't use it when making a single attack using single shot, semi automatic or narrow burst.
It seem as if it is also not used when you make a wide burst attack (but you still split the pool).
It also seem as if it is not used when you make a full auto attack (but you still split the pool).