Meta Research Scientist I interview questions

I was interviewed by a specific team because I was in the interview process for a specialist. This may not be the most common case. During the onsite interviews: I gave a tech talk and had one coding interview, two system design interviews in my domain, and one behavioral + coding interview. I also had lunch together with the hiring manager and a team member.

A recruiter reached out to me. I had one screening interview that went well. After the interview, recruiter asked me to fill out a form about my immigration status (I was on a student visa with 2+ years of work authorization after my graduation). After that they asked me to fill out an additional questionnaire tailored for O-1 visa. All this legal back and forth took approximately a week. After that I got rejected without any explanation of the reasons.