At my situation, I happen to trigger the hunting event only after finishing the wraith fever quest. It's not when Bernard gets sick, but it's a quest that you need to finish for him by giving him 10 spectral syrup.
Yeah. I changed it recently. I wanted it to be available after the sickness event is done, not after doing the quest but I kinda screw it and it's available only after doing the quest with 10 spectral syrups. I'm going to change it again in 0.17, so it's only after curing Bernard.
The change is because it was possible to meet Bernard in the hut, even if he was supposed to be sick and in bed.