Booking.com Software Manager interview questions

After the first interview with the HR, I was scheduled for a phone interview with the hiring manager which was changed twice and also was converted to a video interview. At the time of the interview, the recruiting manager joined late and then without any prior information, one more person joined late too. Why not mention properly how many interviewers are involved? The interview was hardly for 25 minutes or something and candidates are being judged on that!Just a waste of time