Try it for yourself, see if it works.
Its any command I use at all, but here is one I have been using
/execute @a ~ ~ ~ playsound minecraft:entity.player.levelup master @a
blockdata ~-1 ~-1 ~6 {Text1:"{\"text\":\"[Settings]\",\"bold\":true,\"color\":\"aqua\"}",Text2:"{\"text\":\"Flashing Colors\"}",Text3:"",Text4:"{\"text\":\"Enabled\",\"color\":\"green\"}"}
I think 1.7.2, I just opened the world in 1.9.
16w02a
Yes, and once recently to clone the blocks back.
http://www.mediafire.com/view/4055482l9xcxh54/nativelog.txt
http://www.mediafire.com/download/fg33amvp73amwcb/2016-01-19-1.log.gz
Do you think I should use 16w02a to generate an air world, then clone in all the stuff with MCEdit?
http://www.mediafire.com/download/g83atay63a60saj/r.3344.-15934.mca
But should there seriously be that many? Its a world filled with air!
The world has a "spawnchunks" setup at X:1000 Y:10 Z:1000 and a 300 block radius lobby located around X:-800 Y:60 Z:-200. There is about 50 command blocks running in the spawn chunks. If you want the actual world file to look at, please let me know.
That didn't work either, same error.