And to demonstrate the point even further, I started a quick single player huge game, saved a recording and glued two screen shots together. However even in that quick one that I started, one of the AI players got a bugged start...
So here is the huge map where all of the starting positions can be clearly seen:
As you can easily see from this image, a normal starting position in a random map is terran HW + astroid + ice / volc. Also if you counted the planets you'd see that the planets that are part of the starting position, are not counted towards the total number of planets in the map (random huge single = 58).
And here is a closer look of the three top ones, and you can see the that the one in the middle simply has one phase lane missing:
So there is clearly a bug in the random map generator.