[1.0.1.8] Human Story Event Triggers?

[Nachtjager]

I'm learning the game while playing on full-manual for everything, which has led to some restarts as I figure out which dumb mistakes have been holding me back. The most recent example is that I got locked out of building any new ships with a warp drive because I didn't have any access to Emeros Crystal in my starting system and I couldn't obtain any more through trade because I forgot to retrofit a commerce centre onto my starport. Lesson learned! Luckily for me in that game, the Ghost Fleet event had fired. I paid the money, absorbed their faction, and was able to construct new ships through their spaceport and work my way backwards to my home system with exploration and construction ships until I figured out where my blockage was.

My question/possible bug for this thread is: what are the conditions which should cause the Ghost Fleet story event to fire?

I ask because in my first two games, the event fired as soon as I made contact with the Ghost Fleet faction. In my current campaign, started with the knowledge of all my mistakes in my starting campaigns, I've made contact with the Ghost Fleet faction but nothing happened. I'm curious if I didn't get the event because I didn't have enough money at the time of meeting them or something. At this point I'm worried about getting locked out of that story content and missing the artefact that comes with their base.