Tri-Alpha is still supposed to be aneutronic last I knew.

That pdf appears to be a rather specialized report on the development of just one aspect of their concept. Tri-Alpha is supposed to achieve aneutronic fusion by combining the Field-Reversed Configuration concept with the Colliding Beam concept. Collide two plasmas into one FRC and then collide ion beams in the plasma. The C2 experimental device is for developing the FRC part of that and apparently does not (yet) have the colliding ion beam stuff. The use of deuterium would be a natural part of such testing.

But this mixture of techniques, combined with Tri-Alpha’s secrecy, seems to have led to a great deal of confusion among those who follow fusion tech, as one D-T fusion concept uses the colliding FRC variant to achieve neutronic fusion on its own. That’s what Helion Energy is attempting, as a matter of fact.

So this report does not necessarily conflict with Tri-Alpha going for aneutronic fusion.

Edit: a link to an old NBF article that mentions this…

Tri Alpha Energy raises $40 million in Venture capital for nuclear fusion