I seem to be experiencing the "AI passivity" bug as well, 45 minutes in and no waves. One of the AI's appears to be a turtle, but not the other, so this strikes me as odd. I'm not finding the "Failed Assertions" log being discussed here, though, where would that file be generated?
Edit: Or maybe we just had a fluke AI draw. I just checked the high score table (by which one can learn what AI types one is facing), it turns out we've got a turtle and a support corps. Correct me if I'm wrong, but if there are no waves to support the support corps would be passive, yes?