So, I actually felt this interview process started off well - the contact who reached out to me after my application was very responsive and clear. After the phone screen, I had an interview with the person who would be my manager, and that also went fine - lots of standard design questions and referring back to previous experience to answer them, but I did think it was strange that there was a repeated emphasis on being able to work with web, when most companies are trying to be mobile first. And most designers/researchers are going to usually have their base knowledge in designing for web.
Maybe a week later a completely different hiring person reached out to me to have a conversation about salary, which I felt was late in the game. It left a bit of a bad taste in my mouth that I didn't want to give a range at first, was told they don't have a range and pushed to disclose, and then after I did, the person came out with a range they claimed didn't exist before. I get companies want to pay you as low as they feel is reasonable, but that felt a bit "yikes"
However, where it went downhill for me was the takehome assignment. I work in tech, and usually for design roles like this, you're usually asked to prepare a portfolio/presentation of 1-2 projects to play back to interviewers based on stated criteria from the company. What I felt was weird was that this assignment was basically not a design challenge or a true task, but asking you to share materials from a previous project you've worked on. Though they did say you could redact certain pieces, I found this inappropriate given that most of this work is naturally going to be under NDA. Also, sharing some of the pieces they said they wanted to view could definitely get you fired at a lot of places.
They made a decision on whether to move forward just by looking at this material. I find this odd because you usually want the candidate to present the project to you for adequate context, and to be able to ask questions (and not to mention be sure someone's not just ripping off work from projects that aren't their own and submitting it).
I noted my NDAs, submitted the pieces I felt comfortable with, and offered to discuss more in an interview. In return, they chose not to move forward, but the feedback was vague. I got a bit of a sense that they're not used to hiring for these particular types of roles and weren't sure what they were actually looking for. In the end, I feel fine with just having it end there.