Thanks, and I hope you're right! Especially since when I got to the site of the second (and only other) city I had spotted in spectator mode, there was absolutely nothing there.
Looks like I'll be resetting our End dimension when we get 1.13.1.
MC-122625 mentions ALL chests facing certain directions being affected. In my case, only some are affected. I have stacks of chests all facing the same direction, and only a few are affected by the rearranging bug.
I hope this is actually the same issue and has been repaired, but since the behavior is at least somewhat different to what is described in the other report, I thought I'd better mention it.
I have also had some chests turn up half empty, which is different from this and I know has already been reported by other(s).
Same thing has happened to me, only I have NOT used the "optimize world" tool. Only converted the world to 1.13 by logging in after release of the new version. I have only found one chest affected this way so far.
I have also found several affected by the other referenced bug, where the top 3 rows of a double chest swap with the bottom 3 rows (but all items are still present). I have not been able to identify any pattern to which chests are affected, but I converted copies of the same world multiple times and had the same chests affected each time.
Still happening in 1.12.1. I used to bring horses through the nether all the time in 1.8 and before. Spent some time away from Minecraft and now, my first attempt to bring horses home, and even after making the portals all wider, I've had 4 deaths and only 1 successful transport – and that one was a very near miss; I was able to push him out of the portal with half a heart of health remaining! This is VERY frustrating, given how far you often need to transport horses to bring them home in the first place.
Still present in 18w31a. Very confusing to see these at startup.