TuSimple Research Engineer - Machine Learning Engineer interview questions

The hiring process is very unprofessional, and you will feel very disappointing if you don't have an offer at hand. OA, initial phone screen, then 1-hour interview with the recruiting manager. I asked how long is the entire hiring process, and he said it's 3 weeks in total. After that, I was completely ignored, with no word on next steps or even their decision not to move forward. I thought it's a rejection. But after 4 weeks, the recruiter reached me to schedule the second round of interview. They gave me a HackerRank link without any instruction on how to use it. I spent 10 mins to establish video call with the engineer. The 1 on 1 coding interview was very easy. I finished 3 coding questions in 40 mins, and there's still time left. The interviewer was nice, and we discussed some background about the company and their projects. Everything goes fine and I performed well. However, I got rejected the next day. The interview experience was terrible. It takes long time and I am not clear what kind of people they really want. Maybe they have too many candidates at this moment, and therefore do not respect people. Maybe they have already made a decision before interviewing me. The good thing is, I got offer from FAANG. Their hiring process is much much much better than this company.