One interview with the Human Resources and the supervisor about technical stuff and general questions, and a second interview with the Supply Chain Manager to talk more in depth about experience and how the team works

Standard interview process. Hr screening call, then interviewed with 3 people in person and was given the option to do the 2nd interview on the spot. I received an email literally an hour later saying that I was selected and that they will be starting the background check. 7 days later, I receive an email that the background check was complete with no issues. The following day HR tells me that the hiring manager decided to select someone else. Completely unethical and unprofessional.