Board Thread:Theories and Speculation/@comment-45382951-20200609150217/@comment-32685487-20200610212256

Curse Mark Lvl 2 forces them into Sage Transformation using Oro's Sage Chakra. Sasuke is not a sensor at all to begin with, but he could only sense massive chakras like Naruto using the Kurama chakra as Oro pointed out. So there is nothing saying that if Sasuke WAS a sensor he would not have been able to sense Natural Energy, in fact when Kurama built up a ton of natural energy Sasuke sensed that too. Jugo's DNA is part of the Cursed Seal, Sasuke is compatible with it.

https://naruto.fandom.com/wiki/J%C5%ABgo%27s_Clan%27s_Kekkei_Genkai

https://naruto.fandom.com/wiki/Sage_Transformation

https://naruto.fandom.com/wiki/Orochimaru%27s_Juinjutsu#Transformations