Wasn't that a Mega Event?
There were two such events. One was a regular random event, which provided some small bonuses every other turn to some of the receiving race's abilities. The other was a Mega Event, which provided a bonus to all of the receiving race's abilities each turn.
In any case, I didn't had any issues with those events either. The receiving race was almost always the weakest one in the game, which meant, that the bonuses were too little, too late. That race usually got conquered soon after the event happened. Either by me, or one of the others.