TL;DR Unprofessional/irrelevant interviews; Waste of time.
I applied for a senior position on machine learning, relevance ranking/search, data scientist.
The process is: HR --> a series of tech interviews (manager, director, engineer) --> cultural fit.
In-depth tech interviews with engineer and manager were unfriendly and irrelevant.
Engineer didn't seem interested in any communication or my background match. I was asked a few system design questions -- which are still relevant at this point, and many random questions (NoSQL, Postgres, consistency, etc). I used these in earlier projects so I can still answer majority. Engineer didn't seem interested in any communication or follow-up and kept saying "let's switch gear" every few minutes and moved between random topics.
Manager did one initial tech round, and an additional impromptu extensive tech interview which is strange and irrelevant to the job I applied for. I got asked extensively on Ruby on Rails details (digging deeper and deeper on specific Rails aspects until I couldn’t answer) and full-stack Web, which has zero relevance to the job and people's general expectation of the role. I worked on multiple Web projects before, so I could still answer majority of questions, but failed to recall a few small details as he kept digging narrower. I was then asked for code samples and job references.
Throughout the process, the friendly HR told me the feedback is positive, but final decision was delayed. Later, they told me they could not give offer, as they need to hire more senior/manager people for the new team. And the manager insisted on providing me interview feedback, which roughly says “lack of in-depth knowledge of Rails, and Postgres; lack of production code samples.”
I find it amusing since these were never part of the job requirement, and no employee is legally allowed to share “production code” to future employers.
I was left with the impression that the team doesn’t know what they’re doing or what they want for a machine learning/recommendation/relevance ranking role, not even to mention a senior one. I have closely-relevant research and project experience, and abundant experience interviewing for similar positions with other reputed experts in the field, so I believe I know what a good interview experience looks like.