I figured more people would chime in here. As far as the cop bug, that must be a glitch because I've never heard of this before and I've played Chinatown plenty of times with 1.3.1 and the cops always wander off. Did you start the quest line with Ji Went Ja or is it simply not there? I checked the dialogue file and you should have the option to begin it. Another strange glitch I've never seen before. I haven't touched the cops or Ji Wen Ja in 1.3.1 so I'm not sure why you're getting this issue now.