How can they import a Xiaomi phone from China, when Xiaomi doesn't sell the Mi4 outside the Chinese borders?
I think that they bought the phone from a webshop including an unofficial international ROM.
I don't even think that the original rom is rooted. You need to perform a few steps to root it or you need to download the xiaomi.eu rom. This was is indeed rooted and contains the weekly build.
Edit:
I just read the original article.
Thanks guys for not editing your message and spread this strange news into the world. Thank you for trying to bring Xiaomi down without all the facts...
Bluebox DID NOT purchased the phone at Xiaomi, but at a reseller.
The reseller could changed the rom with spyware.
The conclusion of Bluebox and your post should be the same:
This obviously means buying Xiaomi devices from a retail location is not recommended and only purchasing devices directly from mi.com will result in the supply chain integrity of the devices enterprises require.