i have so far found three bugs with the mateus santos quest:
1: when you meet ambroz bricenos for the second time after you agree to kill him, he doesn't even bother talking to you, but immediatly attacks you.
2: after you agree to kill jeffrey bampflide, (the second mission) and you exit santos' house, the quest log is updated, and you failed the quest because the months had passed. (they actually didn't, but the quest is failed nonetheless)
3: in santos' house, the battle mode is always on, while noone attacks you at all, and you can simply speak to everyone as normal.
1: when you meet ambroz bricenos for the second time after you agree to kill him, he doesn't even bother talking to you, but immediatly attacks you.
2: after you agree to kill jeffrey bampflide, (the second mission) and you exit santos' house, the quest log is updated, and you failed the quest because the months had passed. (they actually didn't, but the quest is failed nonetheless)
3: in santos' house, the battle mode is always on, while noone attacks you at all, and you can simply speak to everyone as normal.