So basically I created a custom map just for testing the system, using tiny map which could just support two players, and it feels like some kind of arena map in other games if you know it. But what confused me is that no matter how I change the settings, or change these position numbers' order in the editor, it seems that I always spawn at one dedicated position, rather than random position from the two spots.

So it makes me wonder the logic of how it determines spawn positions, and I want to know if I missed something in map editing to make the spawn is randomed rather than the situation I faced. 

I tried too and I think that the spawn points are placed automatically from south to north.It's maybe a bug ?

same problem, those starting numbers annoyling rearrange themselves, i hope there is a fix soon