I was approached by their DS lead on LinkedIn. He gave me a question to think about one week before our scheduled video-call interview.
Rather than a normal interview, to me it was more like a knowledge transfer from me to the interviewer. Yes you heard me right, from me to the DS lead. One could tell he doesn't have much experience in ad tech, and was taking notes while I mentioned basic concepts/jargons in Ad-Tech. We talked for about 30 minutes before he had to wrap up for his morning routine meetings.
Note that we never talked about the question given to me a week ago. Plus he never told me if they planned to move forward with me on the hiring process. The entire process made me wonder whether that Data Science Lead ever envisioned me as a potential hire, or he just wanted to take notes of some domain knowledge from a local guy in the same line of work.