All overall the whole interview experience was very poor and disappointing, conducted in a very arrogant way by the company.
I had a first introductory telephone interview, pretty standard (with human resources) followed by one hour technical interview with this woman who supposedly was senior/head of data science. Most of the interview was around examples of tasks that I had been dealing with in my career and how I had approached and solved them; however, in almost the totality of cases, I was promptly interrupted by her with the claim that my approach was wrong (without even listening to what the actual methodolody was): as such, I quickly got the impression that she might have been reading on a list of answers written down a paper and as soon as I started diverging from what she expected then the answer would be classified as "wrong".
Anyway, after such interview I was assigned a homework challenge to submit in a couple of days: you are given a set of extremely poorly structured time series data with the objective of returning an unspecified "prediction model" without even knowing what the outcome variable is, let alone the features that you need to use. In order to better understand the task, I sent a couple of e-mails asking for a more detailed description of the expected deliverable - to which I got no answer whatsoever. Nevertheless, I decided to work on the challenge by trying to describe my thought process, the type of model that I thought one could use, the precision expected by such algorithm and so on; I ended up building a python package performing ARIMA predictions with the user being able to choose by themselves what to consider as features and what to consider as response. In addition, I submitted a presentation with graphical visualisation of simple cases, together with thorough descriptions.
Two days after I received a prompt rejection e-mail stating that, despite the perfect quality of the code, the solution was "wrong" - without any further explanation whatsoever. Since I wanted to honestly understand where my mistakes lied, I asked to explain what went wrong, also emphasising that the task was completely unspecified in the first place (and that they did not answer my request for better clarifications); in turn, they replied that no explanation was due and that I myself was incapable of understanding the subject at hand.
Given the above, I had a general impression that the interview and the team they have is made of people who have absolutely no understanding of what they are talking about, with in addition the arrogance to not even listen to your arguments or the intellectual honesty to discuss scientific solutions. I have been in my job long enough to safely say that this only happens in unprofessional environments, with people who have no scientific education at all but that, for whatever reasons, occupy lead or management positions.