Palo Alto Research Center interview questions

One 1-1 interview with Principal Engineer. Afterward another 1-1 with group manager. Then, 1 online take home assignment. After this, 6 interviews with various people in the group and a couple of director. The whole experience took way too long and left a bad taste. Interviewing with this many people is both a waste of the candidate and the interviewers time. After the take home test and the 1-1 with the senior and group manager, I was told by HR that I had it in the bag and an offer letter was coming. But then suddenly, I get told that I am scheduled for a full day interview with people ranging from department directors to various senior scientist. The interviewers were nice and they were interesting people. But frankly, the 6 1-1 interview seems to have been scheduled as a way of stalling for time. Since, afterward, they took 2 weeks for giving me feedback and ended up not giving an offer.