A17 D3023, I placed the General’s Gong, waited for the campaign prompt to appear, and then ignored it entirely. I then moved my forces in to the spawned camp, which had an ogre or two, an orc cleric and some purple kobold archers. The camp was hostile to me, so I purged it entirely. After the camp was cleared, I clicked through the campaign prompts and was told I’d defeated the camp and completed that campaign objective.
In the past, with previous gong challenges, when I’ve waited to finish the campaign prompts before attacking, I’ve noticed that more enemies usually spawn in on top of those already in the camp. This time, it appears that second wave didn’t trigger, maybe because I’d already killed the leader?
In any case, I’m not sure if this is a bug or not, so I’m posting my experience here to talk about it first.