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Find array called quests (ctr+f and type quests) then count from 0 to 14. You will have either [0,1,3] or [0,1,2,3] (depends if you saw heat scene). Delete everything in between 14th brackets so you will have only []. After loading the save you should go to the quest tile and you should have "Hollow" button (after loading check quest journal you shouldn't have Mad Cow entry in completed). Quest tile: Second red tile on the left from Marefolk Village with Brint.
Beginning of quests array and how to count (I added space for better visuals on empty brackets):
"quests":[[0,1,2,3],[0,1,2,3,5,8],[ ],[ ] ...
[0,1,2,3] - 0
[0,1,2,3,5,8] - 1
[ ] - 2
[ ] - 3
etc.