Let's not jump the gun here, who knows what script of the instances those players managed to enter before completing the 10 hour war. Hopefully the actual raids will be OK, we will find out soon enough :)
I'm pretty sure that's not a bug though - or at least it's worked like that during vanilla, as we and lots of other guilds did the same to not have to deal with crashing servers then. On my realm back then, AQ20 was fully cleared just a couple hours after ringing the bell, long before the Ten Hour War was over for example.
Seems china got all the world first kills, the race is over. Now the big guilds can focus on farming those "legendary" mounts for a month.. yay..