I was interviewed by phone by a headhunter who, though he said was with OS, was actually a contractor. Then I was interviewed by phone with the CS team manager, then again by her in person, then by a CSM and someone on the support team.
I'd assumed the in person interview was considered the second, but I was told afterward that they'd let me know if they wanted me for a second interview. I never heard back.
Applicants should be aware, I asked the headhunter what the salary was for the position to make sure the application process was worth my time, and he inflated the actual number by $15k and mistakenly said part of it was variable, which I didn't find out about until the in-person interview.