Copy-pasted blueprint of working space platform.
What happened?
However, because of lack of constructing materials, cargo bays, I happened to observe how exactly they were constructed.
spoiler
— cargo bays were constructed by the rules of construction bots, from edges to centre. Which led to full inventory of platform. 
What did you expect to happen instead? It might be obvious to you, but do it anyway!
Build space platforms from the centre of the platform hub.
