It could be for survey purposes. To gauge how well the existing mechanics perform on such difficulty, and to get data on how players handle it. Or, you know, maybe they just forgot that there was still this fight intended for higher levels that should have been nerfed or left out of the EA altogether.
Perhaps. It has clearly shown how broken mechanics are in this game currently.
For many people this encounter is hard if they try to go at it as a direct encounter, which dialogue encourages.
But game design encourages the opposite and there are any number of ways to absolutely devastate them with no challenge while essentially not caring about the 5e rules.
Barrels
Shove/Throw
Sneaking Madness
Infinite Imps at Infinite range
Army of Undead
Army of Immortal Undead Children With Clubs
Solo (non-EK) Fighter With Scrolls and Consumable
A Combination of Any of These
