Amazon Software Development Engineer interview questions

three online assessments, first debugging code, second leetcode style algorithms and data structures, third work simulation. Final 45 min interview after passed all three where they asked about leadership principles and more traditional algorithm and data structures..

One interviewer end my interview 20 mins earlier than expected and he failed me. But other interviewer think I did pretty good. So they downgrade my level. I could not get how the interviewer got the conclusion that I'm not good enough for the role within only 40 mins? If they can decide in 40 mins, then why the interview process designed as 60 mins? It's unfair and ridiculous!