According to their Hiring Process PDF it was supposed to be a first interview just to find out about you as the candidate, but it was very technical. Not according to their Hiring Process PDF and catches you off guard

Very long interview process - 3 separate zoom intervals over the course of a month and a 4th in-person panel interview. With each interview, recruiter mentioned that the salary rate was changed to new lower range. (Very "Bait and switch") Prior to the 4th in-person interview, recruiter informed me that it was going to be an even lower range. During in-office panel interview with 3 directors, and executive, I was asked at the end of the interview in front of the panel my salary requirements. I thought was a little awkward considering this had already been discussed with recruiter and normally compensation is not discussed in front of a room full of several other employees at different levels within the company. After 4th interview I was told they would be in touch within a few days with the next steps. Their office setting is a sea of cubicles with nothing on the walls in the interior of the space with glass offices around the perimeter for the executives. I found the cubicle areas poorly lit and un-motivating.