yes that is one of the possible rewards.
it is completely intended, would be a funny bug if it was unintended.
it was mentioned in the Writhing Wall post
https://www.elderscrollsonline.com/en-us/news/post/68785?cats
A chance for a sellable treasure of varying value (one is guaranteed in Glorious coffers)
This reward has a very low chance to be replaced with the Coldharbour Surreal Estate if you do not already own it, or with a sellable treasure of exceptional value if you do
edited to add:
Coldharbour Surreal Estate does not have a furnished version.
it is also available for 1 million gold, most people probably buy it with gold (i know i did).

Mrnetch3211 wrote: »yeah I got that 5k skull as well
I hope this isn’t the treasure you get if you already own Coldharbour Surreal Estate… 😅
katanagirl1 wrote: »
I hope this isn’t the treasure you get if you already own Coldharbour Surreal Estate… 😅
Awesome! I also got it yesterday in PC EU. It was totally unexpected because my rng is always kinda bad.xbluerosesx wrote: »I got a the Coldharbour Surreal Estate house in a glorious box. (...)
I still have a bitter taste in my mouth that all the people who have owned this house for years received absolutely nothing of real value from the event... It's not that I begrudge the new players getting something great - but what do the loyal players who have been with ESO for years or even a whole decade get?
I still have a bitter taste in my mouth that all the people who have owned this house for years received absolutely nothing of real value from the event... It's not that I begrudge the new players getting something great - but what do the loyal players who have been with ESO for years or even a whole decade get?