I don't know if it was bad luck, but I think the chances of this random event are a bit to high in the stock mod and in TDM.
I have had solo games where I lost 3 star systems to this random event. When I got the 3rd notice, I just quit as it was becoming very much not fun. (I could certainly have still won, but I didn't feel like bothering)
It just seems like in a cluster of 30 systems, having 3 of them go nova within 60 years is a bit excessive
