It seemed random to me; but coincidental. I had two animals fight six months before, another pair four months before, and another one month before. This is not what I consider hard-coded; just likely as you get a larger zoo and don't attend to babies becoming adults and vying for alpha status. You get a full year notification that the inspector is arriving.
What frustrated me was when a baby ostrich was literally standing next to their water; and complained of being thirsty. Then it complained of being dehydrated, and was getting stressed. The inspector was due. And literally when I'm like; baby is going to quarantine; protestors show up. So is it hard coded? No. Still find that coincidental, and see the baby as bugged on sight paths or knowledge of space.