Hiring committee's job is to take the interview feedback and provide a "Hire" or "No Hire" decision. 99% of the time this is done entirely based on the interviewers' feedback without any further interaction, but occasionally the hiring committee will reach out to ask clarifying questions or provide feedback on the report. Sometimes that feedback is along the lines of "this question is more complex than the candidate's target level" and sometimes it's "hey, that question has been widely posted as a 'Google interview question', so people are studying it specifically; you need to stop asking it." Good interviewers will proactively ask for feedback from hiring committees so that they can provide a better signal.

Also, it's worth pointing out that there is no "one" hiring committee. Many people are in the pool for that task (it counts as a "citizenship contribution" during perf) and you meet for a few hours once every few weeks and grind through a stack of feedback. That's why he asked multiple times; he effectively asked committees made up of different sets of people.