Fortinet interview questions

Went to their open house and followed up with HR. The hiring manager had me in for a technical test which was about 1.5 hours long and had basic math questons as well as questions related to scripting and assembly language. After the technical test, I had a talk with the manager who asked very basic behavioral questions. The only problem was that the hiring manager's accent was very strong (chinese) and it was a little hard at times to understand him so I had to politely ask to repeat the question if I didn't understand it.

Initial interview was a written technical test with a 2 hour limit (5 coding questions across 3 languages, plus an "optional" bonus question to be submitted after the time limit). The next interview was a resume discussion with a manager that included some technical questions, but was more of a screening (why this wasn't the first step, I don't know). The final interview was a panel interview to go over my answers given in the written test. Between the three interviews and working on the bonus question, I invested at least 10 hours of my time into the process. I received a boilerplate rejection email a few days after the (seemingly successful) 3rd interview and the recruiter would not provide feedback on why they did not want to proceed, which I found disappointing. The position sounded like it would have been alright, but their people skills appear to be a bit lacking.