I've got a related question. We know that if there are Qunari and Tal-Vashoth in the same area they are bound to fight. That's what you see in Seheron.
But are Tal-Vashoth actively hunted down by their ex-countrymen just like apostates?
I think that the Tal-Vashoth and how they interact with Qunari really depends on the situation at hand.
Bull's comments about Seheron imply that the resident Tal-Vashoth are mostly made up from those who burned out (like he nearly did) and went rogue, so from their point of view they aren't so much attacking the Qunari as acting in self-defence against those who seek to kill them for desertion. In DA2, the leader of the Tal-Vashoth in Kirkwall even states their belief that Hawke was a member of the Ben-Hassrath before attacking the party.
This sort of thing likely feeds and reinforces the Qunari's propaganda that Tal-Vashoth are always hostile (regardless of whether or not they actually are or not), due to situations where the Tal-Vashoth either fight back or launch pre-emptive assaults, either mistaking or identify others as Ben-Hassrath agents.
However, it's unclear whether a Tal-Vashoth when confronted with a member of the Antaam would actually have reason to fight them?
The priesthood and military are totally seperate entities as we're told, so Qunari soldiers would not be obligated to do anything when confronted by either deserters (or rogue mages) as it is not their demand of the Qun to hunt them.
(Arvaarad in DA2 would imply that while the Qunari force that landed in Kirkwall seems to have been primarily military, they did have some members of the Ben-Hassrath alongside them as they would have been required to keep control of the Saarebas accompanying the expedition).
TL;DR, I think that as long as you're not a Ben-Hassrath, then for all we know, Tal-Vashoth might not have (as much of) a problem dealing with Qunari?