Very unprofessional. Interviews were postponed multiple times.

Round 1 and 2 involved phone interviews based on probability questions and a couple of puzzles.

The on-site interview has yet to happen.

They are very focused on probability and puzzles and don't seem to care about background. My background is in stats and ML, but the interviewer didn't seem to care. After the phone interviews, I asked a couple of questions regarding non-linear models they use for behavioral models, but the interviewer didn't want to answer. It seemed as if HRT people forcefully asked one of their developers to interview me.

Spaghetti in a bowl question.

Pick up one end of a spaghetti strand and you can either join it to the other end of the spaghetti strand you are holding, which creates a loop, or you can pick any other end in the bowl and join it to that. Find the expected number of loops.

Another spaghetti question (I think the interviewer loved spaghetti):

You have a plate of spaghetti in front of you (no sauce!). You pick two ends and tie them together. Then you pick two more ends and tie them together. Continue until there are no free ends left.

If there were n spaghettis originally, what is the probability that you now have a single giant loop consisting of all the spaghettis?