So I got log messages of “The acid-sniper zombie launches a corrosive dart!” but the only zombie in sight was a ‘bilious soldier zombie’. Was it in disguise, or was the sniper just out of sight range?
Unfortunately I got distracted and forgot to take a game save or I would have posted a bug issue.
Indeed, the bilious soldier zombie has a The acid-sniper zombie launches a corrosive dart! message on its special attack, as well as the caustic soldier zombie still does have The acid-support zombie launches a hail of corrosive darts! on its.