The Enhanced Operator Augment mod from the DSC raid doesn't provide additional effects when multiple copies are stacked. The video I linked shows me having 3x copies of the mod equipped, and when not holding an augment each orb of power I collect is still only giving me 1x "Generate Heavy Ammo" buff. When this buff hits x10, it gives heavy ammo, and with multiple copies of the mod it should be providing extra buff stacks per orb of power collected - but it's not - it still takes 10 orbs collected no matter how many mods are equipped. And we know that with the scanner mod, the effect that gives when not holding an augment does stack with multiple copies (stat boost specifies x4 when wearing 4 mods), so it's reasonable to expect the operator mod should also be stacking.