It’s been more than a month that the Lich King’s Necrotic Plague is not working properly, it doesn’t jump into the next Ghoul after killing the previous one as it was supposed to, so it never stacks, making the following achievements impossible to obtain:
And by extension, both the 10 and the 25 man version of the Glory of the Icecrown Raider not obtainable at the moment. I got the 25 man version before that happen to prove that it was working properly but for some reason it isn’t anymore.