Meta Production Engineer interview questions

Received an email from a recruiter asking some basic questions. Received a 10 question quiz that was pretty easy. Then had two interviews: coding and PE basics. The coding one was fine, average Leet code medium style question. The PE basics was not what I was expecting at all. The two people in the interview immediately seemed annoyed and like they didn't want to be there. I was asked system design questions which I was anticipating would be in the next round if I had made it through. At the end of the interview I asked if they experienced any challenges and one of the interviewers scoffed and said 'No, it's Meta the resources are unlimited'.