Amazon Programming Manager interview questions

I was contacted out of the blue by a recruiter, who was very nice. I don't have any background in retail, e-commerce, etc., so I was rather surprised that Amazon was interested in me. The recruiter indicated that there were several opportunities that he thought I would be a good match for, and proceeded to set me up with a phone interview with a manager whose background he thought was similar to mine. The actual phone interview, however, was oddly impersonal. It was rigidly structured -- 5 minutes for the interviewer to introduce himself, 10 minutes for him to ask me questions, 12-ish minutes for a "case" study, and then he allowed me to ask him 2-3 questions. I tried to make it the tone more "conversational" but he seemed annoyed that I was taking him off script, so I stopped because he clearly didn't care about interacting with me in any genuine way. It was a stark difference from my interaction with the recruiter. I was never explicitly told what job I was interviewing for, and the case study turned out to be very specific to the interviewer's exact job. I know that tech companies like to see "how you think" but to me, this just felt like an exercise in making stuff up and pretending that's how I'd legitimately solve problems on the job. i.e., "Fake it 'til you make it." The interview didn't feel like it had any substance, so I'm not disappointed that it didn't ultimately go anywhere.