AI training never seems to settle on a particular Weight

[FieryRMS]

None of the AIs in any generation were able to beat all of the AIs. The weights of the top AI change dramatically in a span of 2-3 generations, and often its an AI you wouldn't expect to perform well. Then in the following generation, that AI is suddenly performing very bad. I expected the AIs to eventually settle at a well rounded AI who is able to get draws against stronger AIs.

My suspicions is that the AIs may have developed a couple of strategies, and each strategy can beat one other, but not every strategy, a non-transitive relationship, much like rock paper scissors. So as the number of one strategy increases, another strategy then beat all those AIs and gets a high position. A visual example could be this meme.