It seems that patch v0.1.4.0 moved the Ultra Sphere to Sphere Assembly Line II, it is no longer possible to craft it via Line I, and the tooltip in tech tree says so as well.
I was crafting them on Line I just yesterday, so this has to be one of the things the patch did, but I did not see this mentioned in the patch notes. Just letting you know to watch out ;-]
Comments
Unfortunate change but probably good for balance. Ultra Spheres definitely made catching some pals quite a bit easier in the mid-game so moving it solidly into the mid-late game area makes sense.