Fortunately, this particular unit has attracted a reasonable (so to speak) amount of attention, and more interestingly opinion is divided with respect to its existence. Distinguished Balkan auxiliary scholars such as Wagner, Kraft (he thought there were two), and Mirkovic all argued (so to speak) for its existence. On the other hand, two of the heavy-weights of auxiliary unit catalogues, Cichorius and later Spaul, both excluded it from their respective discussions, the latter possibly because he was following (to some degree) the former.
As for me, it seems that in my MA thesis (on which the book/project is based) I had argued for its existence, highlighting a certain tribe, the Pasini, mentioned by Pliny and Marcus Aurelius' recruitment of latrones from Dardania and Dalmatia (the evidence for this being found in the always sensible Historia Augusta). What seems to have clinched it for past Conor was that Pliny's Pasini were from the nebulous borderlands between Dardania and Dalmatia. Thus, it would be easy to see, or so I'd thought, how the Pasini of Plinly could be equated with the latrones of Marcus Aurelius, and this mysterious cohort. Luckily for present Conor, past Conor had said that the evidence was suggestive rather than conclusive.
Well, some years later, and with the benefit of hindsight (and more experience), after re-evaluating the evidence, and taking a look at a transcription of the fateful inscription, I'm now convinced that past Conor, as well as Wagner, Kraft, and Mirkovic (the latter three at least with regard to this topic), were full of poop. That fantastic lone inscription simply reads as follows:
[I](ovi) O(ptimo) M(aximo) [-S]cribonius Faustus v(eteranus) e<t> Aure(l)ia(?) Pasina(?) V[---]CRCX [&
How did we go from v..Aureia Pasina to an entire unit (let alone two, for Kraft)? God knows. As with the previous, actual (?), cohort (Sacorum), there are no other records that specifically refer to this particular unit, and as far as I know nothing's been published to reinforce any theories about the existence of such a unit. So, it deserves to be stricken from any lists from Balkan auxiliaries.
Yet again, if anyone out in cyberspace knows anything about this and would be willing to enlighten me, please do. I'd be very grateful.