Online coding assignment. Very theoretical, the few practical questions are very easy. Most of them don't really assess much about your ML knowledge.
If that is passed, then you're invited for a "technical" interview. They call it ML triage, there's recommended ML books on their website (they haven't a clue about those) but questions were not ML related at all, but standard leetcodes instead. The interviewer also had no background in ML.
They then send you a vaguely belittling feedback from your interviewer (with no ML knowledge) about your ML interview (with no ML in it) about why you (an ML PhD with multiple big tech internships) are not a good fit for an ML research internship with them. To say it is a waste of time is reductive, since the content of the interviews are 100% dependent on who's interviewing you.