I've had this issue ever since 2.0.1, although it has gotten better with the later versions. With the latest it seems more varied, so if you reload a few times you will likely get one where you have a little more room to play with. Altering the starting area size however does not appear to make a huge difference in RSO currently.
It definitely appears to be RSO related as vanilla Factorio starting areas seem to work as normal.
