Paranormal Frustration

I didn't try the mod again, but today, for the first time, I played with a paranormal investigator living in a normal house, and... lo and behold, the spectres finally appeared at gigs, and many more creepy dolls, hands, symbols etc. than before! So in my case at least, this bug might actually be connected to sims both living and working in haunted houses, maybe the game gets confused when it's supposed to make spectres appear everywhere, and the only way (for me at least) to avoid that is to have the investigator live somewhere ghost-free.

I haven't gone back to my previous investigators to see if the bug disappears when I change their lot type to a normal home, and I'm not going to experiment any further, especially with a patch around the corner that might (hopefully) address this. But until then, maybe this information can help others who are struggling with the same problem.