I was initially contacted by a third party recruiter. That person later scheduled me to interview with the regional service manager (hiring manager).
My interview with the hiring manager went well. The hiring manager wanted me to speak with both their senior FSE and their junior FSE. I was hoping to get a chance to speak with them sooner. About a week after my interview with the hiring manager, I spoke with the senior FSE. He mentioned some traveling and some on-call. That interview went well. I had to wait a few days to speak with the junior FSE. He mentioned that on-call time was once every 5 weeks. That was negotiable for me.
I then received a call from the recruiter that the hiring manager and the FSE's want to schedule me for a Zoom interview. However, I was traveling for work and had to reschedule my jobs for them. I was still very jet-lagged, but I did the best. During the Zoom interview, they mentioned that there was more weekend work time, along with the on-call time. I wish that they had mentioned that to me from the beginning, as I had reservations about that. They also had a fourth person to interview me during the virtual interview. I would be the one replacing him in the near future. As to why I didn't get to speak with him during the phone interview process, I suspect that the hiring manager felt that the soon to be retiring FSE would have had a negative impact on me; I would have withdrawn my candidacy.
In the end, although they liked me and felt that I was a good fit for the position, they didn't feel that I would be happy working multiple weekends. This is true, but I wish that they were honest about that from the very beginning.