Had a chat with HR and hiring manager. Then, they sent me a take-home exercise. After submitting the exercise, I didn't hear anything back from them, even after sending a follow-up email. 2 weeks later the company sent an automated email saying that the position had been filled. After all of the preparation for the interviews and long hours putting into the data exercise, I think candidates at least deserve a reply from the team instead of being ignored like this.

I experienced two rounds of talking with the TA and then the hiring manager before being ghosted. The interviews were not technical, and only asked typical questions about experience and examples of similar work done in the past.