I found a simple work around for it that seems to solve it with no issues (dammon and ox quest unbroken for me) .
When you go to the last light (there should be a auto save right when you enter the area before you trigger the ox) move forward to trigger the ox so it shows the initiative popup for it in the distance and jump to the waypoint menu and warp to a act 1 zone. Be quick since time is still passing while in the menu, if you do it in time when you warp back the ox is gone and dammon is safe, the ox turned up still in act 3 for the remainder of its quest for me.
This workaround literally saved my life and I made an account here just to praise it - and to confirm that I was still able to find the ox in act 3!!
