Chat with them at university career fair, followed by a computational challenge with 8h expectation. The process was very different (I'd unprofessional too) that I chose not to continue with the process. First after the career fair, I heard from one of the team members that "please finish this exercise and send it to us in a week". No words from a recruiter or anyone asking me when is a good time for me. But I gave them the benefit of doubt. After I finished the exercise and submitting it, the interviewer got back to me with follow up questions that was completely different than the original PDF file they sent me. I asked for some clarification and that are you asking me to complete a second challenge?! The explanations they provided was completely unclear what they're expecting for the follow up question. Then I replied with sorry, I don't have any other time. If a company can't design a challenge according to their most wanted qualities in a candidate, it tells me enough about the company to not wanting to work there.