Totally agree with the last anonymous experience. I had fully the same experience for an offer in Barcelona. Including:

"One day after the onsite, the recruiter reached out and said that the initial feedback was positive and they would be in touch the next day with more information. Four days later, the recruiter reached out asking to schedule a call to discuss 'feedback and compensation.' It was reiterated that the feedback was positive.

I hopped on the call with the recruiter to discuss compensation. No feedback about the interview was given. I was also informed that I was a top candidate and the final decision would be made the next day between me and someone else.

The next day, at exactly 6:00 PM an automated rejection email. The message was clearly not meant for candidates who made it past the onsite, as it read 'We know that filling out an application takes time, and we appreciate your effort and interest in our organization.' Furthermore, I was not given any feedback beyond the standard jargon of 'After consideration, we've decided to move forward with a candidate whose qualifications better align with the needs of the position.' The message had clearly been scheduled ahead of time."

And totally agree with:

"Overall, the interview process was extremely unprofessional. I expected the common courtesy of being rejected over the phone (especially since I had spoken to the recruiter the day before) or at least given some form of feedback as to the deciding factor of their decision. Instead, I was led on by the recruiting team and then discarded in the trash through an automated email.

If you get an offer, think carefully about how they treat you through the process. It's very reflective of the organizational culture."

The coding challenge was on Codility. It had three questions: two algorithmic and one SQL-based.