Apparently, this is not just a shock question. I filed a public records request, and this guy admitted to letting a dog lick peanut butter off of his ballsack. Nevertheless, he was still hired and is currently serving as an AZ state trooper.
Creepy Dan Caputo is really working wonders for this department!
If asked during the "in-test" phase, the question "Have you ever had sex with an animal?" is still a shock "control" question. However, any admissions will be duly recorded and may be disqualifying.
However, I'm not aware of any agency that currently uses this shock "control" question. The U.S. Secret Service polygraph unit, which was infamous for asking this question, appears to have abandoned the practice.
In the case you cite here, it seems likely that the admission came in the context of the "pre-test" interview, which I understand in the case of the Arizona Department of Public Safety, may include a discussion of "sexual activities of concern."