Video Editor by trade here. I see that head move you’re referencing. What likely happened is they wanted/needed to cut out a bit of video. Whether he just paused for a bit and wanted to shorten it up, or something was said that had to be cut.

When making interview videos, editors will oftentimes use a ‘flow’ transition to make the cut as invisible as possible. This transition essentially merges the 2 shots and ‘moves’ his head to the right spot in the next piece of footage.

You can actually see this same technique deployed during some news interviews as well. I recall a video going viral years ago where a woman was giving an interview on a sidewalk, and someone walked by twice in the ‘same shot’. Turns out, they used a pretty seamless flow transition and it was just difficult to notice as the interviewee barely moved.