one of the bad reasons for bad hiring practices I've seen is that hiring managers throw engineers into interviewing situations a bit too unprepared, often times with very little interview training/experience.

There needs to be a interview training/mentoring period where you have engineers sit in on interviews to learn how and what questions to ask but without actually having veto/accept power. this allows them to get experience without screwing up the whole interview process.

Most inexperience engineer interviewers think you get the best candidates by having the highest reject rate, and that's simply not true. Only interviewing experience and training can improve this.