I applied through a recruiter. The process took 2 months.

Extremely long interview process with too many rounds. Got to the last round (culture interview) but was given a "surprise" interview with vague description, which turned out to be a technical interview that I was not expecting. The questions in this surprise interview were a world of difference from original job description, or anything that was shared in earlier rounds, or from HR. Hence giving an impression that company does not know what it wants in candidates, despite such a long process of more than a month.

Was then rejected after this surprise round, hence wasting both parties' time and energy. This is not a company I would want to work for, since it became very clear that hiring manager does not communicate requirements and expectations properly with HR, and there are serious issues in the organisational culture. Even if I passed, I do not think I would have a productive time navigating such a chaotic organisation.

Several interviewers were late across different rounds, and one did not show up, requiring a reschedule, wasting yet another week of waiting. Only positive thing was HR was friendly and accommodating, and interviewers were in general friendly and supportive, although signs of overwork and messy organisation could be inferred.

Given the large pool of tech companies hiring aggressively, if you have the technical competence to land an interview at Mistral, I imagine you can reasonably land interviews at other companies, so I kindly advise focusing your energy on those alternatives instead. To save yourself time and energy from such unexpected twists and turns during the interview process. It was really my own mistake to have given the benefit of the doubt and assume for the best, despite having read numerous unpleasant experiences by past candidates on Glassdoor and other portals.