Unofficial Skyrim Special Edition Patch

I reproduced the same error as 13770
Issue #13770: Purity - Quest resets over and over
https://afktrack.afkmods.com/index.php?a=issues&i=13770

1) Talked to Wilkas in Jorvaskr's main hall, asked about work, purity started and was added to the journal
2) Walked outside, Wilkas followed but immediately turned around and walked back inside, quest was removed from journal
3) Walked inside and found Wilkas in the living quarters.
4) Asked about work, purity started, quest was added to journal
5) Walked back into the main hall, Wilkas followed but immediately turned around and returned to the living quarters, quest was removed from journal
6) The above loop doesn't end

Save: <a href="https://dl.dropboxusercontent.com/u/41720073/skyrim/purityloop.rar">http://dl.dropboxusercontent.com/u/41720073/skyrim/purityloop.rar</a>

I will add that the quest does not disappear from the log, it goes into the Completed Ones in a blocked form. Vilkas is considered the player's "partner" after that.
This error does not allow you to complete the purification quest. This error prevents you from taking on partners.

Unfortunately, I wasn't prepared for this bug and I can't find any earlier saves.