Nelson Labs interview questions

Received a phone call from HR for an interview, confirming the position and the time and day availability. Group interview with the hiring manager and the director lasting about thirty minutes tops. Pay was not discussed until offer was given.

I applied, and didn't hear back for nearly 3 weeks. Then I went through nearly a month of interview processes - one virtual with the hiring manager, one on-site, and one virtual with the VP of quality out of state. I was ghosted after the third interview, even after following up with the HR recruiter. No offer, no explanation.