Senior Metal Bellows interview questions

The first interview was a phone screening with the talent acquisition lead. The second interview was with the hiring manager virtually. They were both informative & positive conversations which culminated with them asking what my availability for the next round would be. Early the following week, they asked me to come in for an in-person, onsite interview, which I accepted, and they sent me the names/titles of everybody I would be interviewing with, along with information that I was to be receiving a follow-up from compliance with instructions about an ITAR screening at the interview. That email never arrived, so I asked about it the following morning. They then replied telling me that they had offered the role to another candidate, who accepted, and that they would be canceling my final-round later in the week. So all-the-while, after they proceeded to offer me a final round, they had a mystery, front-runner candidate waiting in the wings. Why even reach out to offer & schedule a next-round interview if you have a preferred candidate in mind? That demonstrates a lack of organization, communication, and overall professionalism with the company.