Hub Group Analyst interview questions

I interviewed with HR and the hiring manager, process was simple. They asked some background information and were friendly. Like normal they did a background check and sent an offer letter.

Two weeks after applying I was called in for an on-site interview. Mostly asked questions about my past projects and skills demonstrated. Ended interview on very weird note, saying that I was there very first interview for the position and not to be concerned if it was "a month or more until I heard back from them." And that if no other candidate applied for the position, then they would have a problem on their hands. I mailed a follow-up thank you card, never heard anything back from them. Found the whole experience very unprofessional.