Trunk Tools interview questions

I had a similar interview experience as others. The hiring process ends up being an exercise in free work for the company. The recruiter reached out to me almost 1 month after I applied. The intro call went well, as did the following interview with the engineering manager. The third step was to complete a take-home coding project, and I was promised a $50 Amazon gift card or a $50 donation to a charity of my choice (I picked the charity). I completed the project and was scheduled for an additional 2 interviews, one to go over my take-home project and the other was an NLP system design interview. The interviewers for the take-home test review seemed more interested in going off-tangent with their questions, like "how is the technology for this specific library implemented?" or "can you explain the mathematical differences between certain machine learning models?". I didn't get a chance to finish presenting my report for the project in the hour's time because of the curveball questions that had nothing to do with my implementation. The NLP system design interview went better. At the end, the interviewer told me that I had designed the best architecture diagram he had seen in all the interviews he has done. The next week, I got a canned rejection email. I got further in the process that some other interviewers have reported, but the end result still leaves a bad taste in my mouth. The job posting is still open, so I whole-heartedly believe that this company is scamming interviewees. And no confirmation about whether they made the donation on my behalf or not.