Perhaps call a short impromptu meeting next time with the caveat that previous responses were all LLM generated. It’s that’s going to be the way forward less employees are going to be needed. Do the brainstorming and disband and wait for better input.
I’d follow up on suspicious contributions w 1:1 discussions. Drill down and see what they know.
unfortunately, I've had a similar experience with a colleague. it is disturbing to say the least. mainly being put in the position to review an obviously ai generated pr without any subsequent or even presequent thought put in to making it into something that will carry your name.