I was asked to complete 4 rounds interviews which took at least 1 full month to complete. I would take time off to attend these interviews, review material on my own time, send follow up emails --- only to be completely ghosted after the last interview. The hiring manager had been following up within a day or two of each step previously, so it was obvious they were avoiding me after that. It took several follow up attempts to finally hear back that they were going in a different direction. I completely respected the decision, just found it very unprofessional in the manner it was handled.