Technical interview. Interviewer & recruiter didn't really provide any prep advice/goals, so I went in preparing for conversation on data engineering projects and likely working with some data - writing queries, working in a programming language to organize or analyze data, etc.
What I got was more or less no questions about experience/projects and a leetcode task that little to nothing to do with anything I'd ever needed to do on the job in the past ten years. Now to be clear: lots of places do this, and there's very little point in wringing our collective hands about it. Sadly, memorizing a bunch of Data Structures and Algorithm implementations and doing a ton of leetcode/codewars problems in your spare time (read: free work) DOES in fact help get hired various places. It was kind of a negative experience, however, for two reasons:
1) I wish I'd had some tiny inkling beforehand that I should be doing leetcode problems instead of, you know, preparing for a job-specific test. Meta does this! Lots of places give you some prep materials or a rough idea of what to expect! It's not hard to do!
2) At the end, the interviewer looked at my solution and said "You know, usually it's only 7 or 8 lines" condescendingly. Look, the price of copying and pasting a problem from the internet/your old textbook was your primary interviewing method is that you're supposed to be aware that not everyone read your mind and memorized that exact problem or something entirely close to it the previous night, and you're supposed to recognize that unless someone did, the solution may be a bit messy.
Overall, the interview experience was at least pretty straightforward: solve this leetcode problem fast enough/with few enough lines for your interviewer to like you, and you move ahead. But the experience was negative: because of
1) The lack of basic consideration to the interviewee (not giving them any kind of expectation or focus for their prep time) and
2) The clear belief on the part of the interviewer that a technical interview isn't about the process or problem-solving: it's about getting the perfect answer
3) The fact that the interviewer felt safe & felt that they were within the bounds of professionalism making a condescending remark at the end of the experience.
TetraScience is doing really fascinating things. I'd happily reapply there: I don't think I'd want to reapply to that team, or at least to get that interviewer again.
If you endlessly grind leetcode for fun the interview experience may be pretty decent. If you don't, or feel your work experience/job skills/personality should be the primary arbiter, you may want to avoid.