The Republic (one of my home made empires) made diplomatic contact with me.
The offered me a small gift.
I made a 50,000 credit trade with them.
About a minute or so later, I went to the diplomatic screen and they were not there.
Nor did I see any vessels or colonies from the Republic out there...
Sorry, I was a past the moment so I did not get a save... it took me a moment to figure out something was wrong. If it happens again, I will get a save game for you.
Remember that the evil which is now in the world will become yet more powerful, and that it is not evil which conquers evil, but only love -- Olga Romanov.