It’s a very minor thing that was noted in Harmy’s thread a long while back. After Han and Luke part ways at Yavin, there’s a shot of an R2 unit being loaded into an X-wing with a guy waving it. There’s extra footage there in the SE and Harmy had an extra frame, making it technically out of GOUT sync by a frame from there on.

It’s not something that matters in reality. I just mentioned it because people sometimes care (many remuxed ESB to fix a similar single frame sync ‘issue’), but the main reason was that in my screenshot comparisons it made the images off by one frame, which is especially noticeable with lasers. But I actually ended up offsetting it to match in the final comparisons, so the note is really not important.