When does a Tech-Adept gain the Machine Trait? Supposedly having the Mechanicus Implants Trait does not suffice. At least the description in the DH2 Core Rule book does not mention anything about the Machine Trait. Also in the Gear chapter of the same book, in the section about Cybernetics I couldn't find anything about the Machine Trait. On the other hand the Tech-Priest in the NPCs chapter and a Tech-Priest in the adventure have the Machine Trait.
So when would you grant it to a PC Tech Adept? And keep in mind that this Trait is very powerful! See fire and mind-psy.