Try that again with max tech and I bet you get 8 research III and 1 SY III. SEIV sometimes has a problem with mixed ability comps and facilitys.
However it appears that as of now you can do this so homeworlds (as long as they don't take damage) will start out with massive build ability. But you will not be able to repair or build a new planet with multiple SYs. However you might want to see if the AI does it because it sometimes is able to do some illegal stuff
