Random would be this Bishops would have had this at least 1 time out of the last 7 rotations.......it's not random at all
Some time ago, in AH2, I had a similar impression. No being a friend of anecdotal 'evidence', I went on and took notes. And being a heavy player back then, I managed to record every map change for months. It turned out to be random, but as with all things random streaks did happen. I blame my cognitive bias to have noted streaks if 'bad luck' more than the overall random effect.
If you want to show that it's not random in AH3 anymore, you need to provide a substantial data sample