Hey guys! Just got my plat on this game.....finally. My last trophy was the Michael Mamaril one which I think everybody is having trouble with post patch. Just thought I'd share my experience with the trophy. I must have quit and reloaded 100 times before I was at the point of giving up. I then fast travelled to the steam plant place and killed one guy. I then returned to sanctuary and BAM there he was. It could have been luck or whatever but I think fast travelling rather than reloading is more likely to get him to spawn. Also killing an enemy might help.
this post was more to give you guys hope that he WILL show up, just keep trying and checking every location. I did it pre lift off and no I don't have any evidence for my theory......except my plat of cause.