Interview process at startups, never had the pleasure, but keep in mind that they are new by definition. It's arguable that many large corporations don't have a good interview process. Imagine a limited funded startup. The amount of time to train a person to be a good interviewer, coming up with relavent questions, calibrating what a typical answer actually is vs. the answers you think you'll get.

If the company is rapidly growing then they may require employees who never been an interviewer to become interviewers (hopefully some shadowing and training is involved).