As the last few episodes of TOS Season 3 are being uploaded to the channel as I type, I decided to go through and process all the final batch of TOS special features.
One of these is the "Extended" version of the unaired pilot "The Cage," which includes an introduction done in the 80s by Gene Roddenberry, clearly done entirely on video. This intro spliced in lots of telecined footage as well though, and of course precedes a nearly hour's worth of telecined content. So I told Handbrake to Detelecine and Decomb, and it should have intelligently detected which parts were what and only filtered each section appropriately, but my output video is noticeably wobbly and choppy around the Gene intro. It seems the constant cuts to telecined footage trips up the algorithms that are meant to tell the two types of content apart, so Gene will suddenly get real choppy, then in the next shot be moving smoothly again. It's very jarring.
So I said fuck it and decided to Bob Decomb the whole thing to 59.94p. It's absolute overkill given the vast majority of the content is actually 23.976p but I can't think of a better solution that wouldn't involve a stupid amount of tinkering.