Now, I do not know what happened exactly. Maybe
1) The assembling machine fed manually achieved the production ratio some time before, in which case the tutorial objective should be marked as green
2) Hand crafting counts towards production rate, which is unexpected and got me to an alien attack largely unprepared. At that moment, I was crafting many research labs/assembling machines. If you assemble all of them (shift-click production) then all the green circuits are assembled before all the final items.
3) Some other bug/misunderstanding kicked in

Achieving a target when you are only halfway through it is very frustrating
