Amazon Senior Developer interview questions

The hiring manager contacted me on LinkedIn. We discussed the role, I sent her my resume and the phone screen was scheduled. 2 days after the phone screen I was told I had done well and I would be brought onsite. 2-3 days passed and no one contacted me to actually schedule the onsite. I finally reached out to the recruiter I was working with and was told that the position had already been filled. Well how about letting me know? 2 days later I was told that another team was interested in interviewing me and wanted to schedule a phone screen.. again !? I agreed.. but the 2nd phone screen was bizarre. Who asks a system design question in a phone screen? I did okay.. but it's definitely difficult to tackle this over the phone. Next morning I got an email saying it's a no-go.. but I should keep applying to positions that interest me. However as I applied to other positions, I got rejects and found out much later from a friend that apparently Amazon has a 6 month cool off period. So why tell me to keep applying to other positions?

It started with a one-hour phone screen, writing code on a shared document on the web. After the phone screen, I was invited to fly to Seattle for a full interview. I told them I didn't plan to relocate from the Bay Area, but I was told I can work remotely, but the team is based in Seattle. 3 weeks later, I flew to Bellevue, Seattle for the interview. However, unbeknownst to me, the hiring manger could not make it. Also some interviewers couldn't come to the office, so it was done via video conference. I thought the whole purpose of flying me up to Seattle is to meet the team in person, but not only did I just meet 1 team member, but also failed to talk to the hiring manager, which I thought was the important part. I had a bad feeling about it. A week later, I was told Amazon won't make an offer, they can't give me any feedback either, except it was a tough decision. The whole process felt quite unprofessional.