The Azem crystal's always been summoning something that's not 'real allies' as far as being completely flesh-and-blood people; illusory is as good a word as anything, we don't exactly have a lot of details on how it works.

Remember that the distinction in Ultima Thule was that Hydaelyn turbocharged it to the point where it was summoning real people and giving them physical bodies, which it's otherwise not capable of doing. Probably the best comparison example there was that back in the Seat of Sacrifice, it could only summon a spectral Emet; in Ultima Thule, Hydaelyn's amp-up let it summon the real deal.