Instruction Partners interview questions

First round was a video interview via Spark Hire, second round was an assessment that took 3 ish hours, 3rd round was an actual interview with people via Zoom, then another 4th round interview. They asked for 4 references prior to the 4th interview and I confirmed with 3 of my references that they responded. 2 days after the 4th interview, HR reaches out to me and says they've only heard back from one reference. I ask them to double check, they say ok, and that was the last formal communication with them. Late that evening I got what looked like an automated email saying my offer letter was cancelled? I was never told there was an offer letter...I hear nothing until about 2.5 weeks later when I receive a generic rejection email. They wasted a lot of my time and all I got was a generic HR email.

3-4 rounds - a video-based interview that questions are submitted, an assignment to submit that had multiple components including data analysis, and a panel interview with a team with situational questions.