Interview panel was scheduled remotely due to Covid-19, and took place in stages over a couple of months due to the company considering me for multiple positions.
Initial interviews went well, and was "approved" for Director-level and VP-level roles within the organization following two senior manager sessions which included coding and architecture deep-dives.
Over the next month, FB decided that no VP or Director level positions were open, but wanted to actively interview me still. They asked me to confirm an email stating that I'd consider an M2 position with the company, despite being in an SVP role at another FAANG. While the comp was 1/4 of my current package, getting "closer to the action" was exciting, so I ended up agreeing to a panel at that level for both M2 Engineering Manager and M2 TPM.
The Engineering Manager interview was very standard: Director-level interviewers looking for soft-skills, management style, culture fit, and the like. My coding interview, however, was bizarre. It started out with the interviewer changing the language it'd be conducted in "on the fly" because she wasn't familiar with the language I had chosen. Curveball, but okay. Next, we couldn't find common ground on terminology surrounding algorithms, and she seemed wholly unfamiliar with why specific types of optimizations were superior with large data sets versus smaller scopes. She spent most of the time talking about how a language I helped create had shaped her career. I don't think the feedback was generally good from this session. For one of the architecture interviews, the interviewer was visibly on his phone for almost every answer I gave, and kept saying "sorry, could you repeat that?" and didn't seem to be paying much attention at all. No offer for that position, and was asked to consider PM.
I declined two pending offers from other companies because PM is my "ideal" role at FB. After a week, FB got back to me and said "oh, actually it is TPM, sorry". TPM is not a role that is very exciting for me personally, but because they asked me to let my other offers expire, I was backed into a corner quite a bit and ended up agreeing to interview for TPM.
The TPM interview panel ended up just using 90% of the (very positive, apparently) feedback from the EM panel. The only change would be talking to the hiring manager for the new role and doing another architecture interview. Architecture went well, and we scheduled the hiring manager interview. Unfortunately, at the last minute the hiring manager was unavailable and an alternative interviewer was scheduled. Unfortunately, she showed up fairly late and we were time-compressed. I had a flare-up of a medical condition and became temporarily unable to speak properly (multiple sclerosis). I asked to reschedule, but was declined by both the interviewer and my recruiter.
Following that, the recruiter let me know that the package would be much lower than we discussed ($1.1MM became $800k), and we set a time to speak about go-forward. Ended up getting ghosted for almost a month, after which the recruiter popped back up and promised an answer "tomorrow". That was weeks ago, and she still hasn't popped back up.
At this point, I'm no longer interested, as I did not feel that my considerable time invested was respected at all. Between not properly accommodating a medical disability and the vague communication, it doesn't seem like this would be a good experience for other senior-level candidates.