Question about Hyperstimm Backlash

So the stratagem Hyperstimm Backlash says that you double your combat drug bonus, roll a D6 and on a 1 the model takes a mortal wound. However, if they have the relic or the warlord trait that gives access to multiple combat drugs they take D3 mortal wounds. Is that D3 still on a D6 roll of a 1 or is it automatic?

Thanks in advance for any responses.

I have always read that as if you take the mortal wound, it is D3 rather than 1