I still don't know what caused the issue in the first place, but please let me know if the version of the game that resets that variable when Aztargal is met for the first time (28/06/19 Fix 1) fixes the problem for you.
The fix works, thank you very much! I also tried the method Nephology suggested on the old version of the game, and it seemed to fix it too, so I guess the bug is indeed caused by going towards the south canals before entering Iustirho's house.
