It seems surprising but according to the article, its possible it was just an accident. The article also says its possible it will be patched out quickly and suggests doing it for the transmogs at least.
This has been known since June Lyn.
In order to que go to Shadowlands and talk to the NPC standing off to the left of the table where the zone quests are.
Hi Noob, that information I was unaware of. I did notice in the article that in order to actually access it one did have to talk to an NPC in order to change to Chromie time in Shadowlands in order to see it on the LFR. I do wish I had known that. I liked that raid a lot. It was so much fun.