P2pah - WoW game designer Jeremy Feasel affirmed from Ruffymmo's blog

To be clear, this isn't occurring from the live version of WOW TBC Classic Gold the match but on its own public test servers. It's here that Blizzard evaluations upcoming changes to the match, such as the coming level cap squish (maximum level players will only be level 50, with all the new level cap being 60 when Shadowlands releases) and the overhauled new participant experience. Butsometime later this autumn, this event will launch on live servers--and when it's anything like what's happening today, it is going to be a bloodbath.

I am not exactly sure when the event is working as intended. Right now, Stormwind is absolutely overrun with ghouls that are rampaging through the streets and slaughtering everything that goes. The auction house, vendors, and even the bank are all unusable--which might be frustrating for players that, once the event is really live, are only trying to go about their day to day company.

On the WoW subreddit, players have also found ways to attract the zombie infestation out of capital cities, making whole areas of Azeroth uninhabitable. It is amusing to realize how much the mirrors a real zombie plague, as slain players and NPCs equally transform into ghouls so their numbers are constantly growing.

Fortunately, WoW game designer Jeremy Feasel affirmed the zombie invasion part of the event is only going to be active for a few hours through the day instead of all the time. I'm actually a little disappointed with that, honestly, because I believe it would be interesting to see yet another all-out, 24/7 invasion that players need to try and contain--something akin to World of Warcraft's infamous Corrupted Blood event.

The Scourge Invasion is only one portion of Shadowlands' pre-launch event. Players may also venture into the arctic wastes of Northrend to battle bosses and make powerful loot, and cheap TBC Classic Gold there is also a new narrative quest to test.