Uber Project Manager interview questions

The first interview was with an HR person. The interview started with him listening to my job history. Halfway through the interview, he asked about salary. When I said what I was making, he said that they couldn't match that and asked if there was flexibility. He quoted a number that was 20% less than than what I currently make and said that was the upper end of the range. At the end of the interview, he asked if I wouldn't mind doing a homework assignment. He said that the short homework assignment takes most people "about 4 hours to do" and could be done "in multiple evenings". I probably spent 6-7 hours writing it up and thought the end result was pretty good. The next day I was emailed a boiler plate rejection letter without explanation. I'm curious if other people had similar results to what I experienced.