DE Bug? - Can't ally/team AI in scenario

I'm running into a scenario editor problem or just something I don't understand in the settings.

I've created several custom scenarios, and I've chosen various player team combinations in those scenarios.

In all of them, teams are preset and "lock teams" is chosen to keep the scenario fair. However, no matter what, when the game launches every AI is set to enemy the human player. It doesn't matter whether or not I choose team I/II/III in the game setup screen, everyone just defaults to locked enemy.

Any ideas?