After I did more testing I'm not quite sure if that happens exclusively. Followed what you did, waited until worms went ahead of a another, slower group of monsters, then used pushback. Before the archer targeted what was "first", but afterward she stopped doing that.
In this case, wouldn't the archer be attacking the vanilla ones closer to Azra, instead of the guys all the way back near the spawn point?
She doesn't target the ranged reverent here, either.
Heh, thanks for answering so quickly and trying to find the source of this problem. It's definitely a nice refresher coming from games where they don't give a crap about fixing anything.
Edit: oh didn't see that new post lol