I'm currently watching NPR vs NPR combat (no idea if a spoiler is in that fight), and I had two Function 4 error : "object's reference is not linked with an objetc's instance" every 15 seconds (each time an action is done by the fighting NPR). I was too slow to save the DB when it was happening, now the fight continues without errors.
DB attached
Edit : It's happening often now, each time NPR are fighting. I suspect it's a spoiler, as something destroyed one of my ship and i'm still neutral with all NPR of the area