Uber Data Scientist interview questions

I got contacted by the HR a month after I applied. The woman I was in contact with (by mail) was nice and easy going. A first interview was scheduled. She didn't call me and didn't even contact me afterwards. I sent a mail to know what had happened, she told me she "was having an issue, as the number is international" (I'm French and live in France). We planned another interview and same thing happened. She sent me a mail to ask me if I could call. I was surprised a company like Uber had issues calling an international number, that's the first time it happens to me, but well, I called with my cellphone so we could start the interview. We started with classic things about my current position and my background. Then, she asked me if I would need a working visa (H1B), I said yes and she told me that it wouldn't be possible right now as they can ask for a visa only in april next year. Then she told me that she would keep my CV and stay in touch with me later on. Overall I was quite frustrated with the process. I expected Uber to be more professional.

Contacted by a recruiter. After the normal recruiter phone screen around background, fit, etc, he sent a data challenge given 2 days to complete. It has two part, sql part and a series of open end questions with a sample dataset. It was not very difficult. Sent it back to the recruiter, a week later was informed to have a phone interview with the hiring manager. The phone screen was firstly around background, the team and then two cases study that uber had or may have in real life. Pretty open ended as well, no need to stress. I think it went really well, especially got really positive feedback from HM directly in the middle of it. So after two weeks, I was really surprised to get a rejection email from the recruiter. The recruiter was not very responsive, and it would be really helpful to get some genuine feedbacks.