Hard bots only building skirmishers?

So I'm not a good payer or anything, I mostly just play with friends or in bot games, never touched ranked. But I love the game, and have done since Age of Kings, and like to think I'm getting a little better.

Most of my games right now are 2v2s with hard bots, and I've noticed that in most games the bots tend to just mass elite skirmishers, regardless of what I'm building. It can be annoying, as the bots can micro them very well, but I just thought it was strange that it seems to be happening every game. Anyone else notice this?

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EDIT I'm playing on DE with the DE AI.