When two speakers sit far apart, Katto stacks two halves of the frame. The cap meant to stop them overlapping measured the gap between the two people instead of the width of the picture they both have to fit inside, so on a 1920 wide source each half was 1215 pixels and up to 508 pixels ended up in both halves at once. On screen: the same person appearing twice, or a body cut at the inner edge.

Measured across 297 split clips already served, 92 of them (31%) were in that state.

Fixed, and checked by replaying 48 clips with the fix off and on: 45 came out identical and the 3 that changed were exactly the 3 that overlapped.