There were 3 rounds of interviews. First round was cordial enough. The second one had a good atmosphere but changed towards the end. The first red flag was that the interviewer asked for my salary expectation and became defensive/annoyed when I gave a small range instead.
Second round of interview they asked me to come down to the office. Second red flag: the receptionist forgot that I was coming (I sat around for 40 minutes thinking that they maybe making preparations). During the interviewed, I was questioned by my "future" colleagues as well as the boss and big bosses who flew in from the US office. One good thing was the questions were very inquisitive and thought-provoking, which I appreciated. One irritation was that one of the interviewers was
constantly playing with their hair during the interview. At the end of the meeting, I was rushed out of the building. It felt very disrespectful, as the interviewer ushered me out of the building into a thunderstorm without even offering refuge for awhile. This kind of things you don't need to ask, as it shows if they have empathy. From then on, I knew that this wasn't a place I wanted to be at.
By the way, most companies in Germany cover your travel expenses when they ask you down for an interview. But LI-COR does not, not even for the train ticket. They ignore your emails when you ask about this policy.