Forgive me if this has already been reported, but I didn't see it on the unofficial bug list that was stickied.
The wiki states:
In game 902, my Civ went to battle with another civ that had 8-10 more techs than us. We won the battle and did not receive any new technologies. We did get the era victory, but that was it.The winner of the battle gains all the loser's Wonders and immediately learns all technologies known by the loser.
When I view the world techs on the world screen, I see a '+' next to all of the techs that they have that we do not. Does this have some sort of significance?