I can think of a number of novels where it's obvious some scenes got moved around for plot reasons, and their were continuity errors or other ways in which the

I can think of a number of novels where it's obvious some scenes got moved around for plot reasons, and their were continuity errors or other ways in which the seams showed. But novelists only have to deal with that for maybe a year or so; programmers have to deal with this problem for potentially decades, and at that point it's a completely different problem just because the scale is different.