Ok I admit I never do this. I just started playing the Yor on sandbox. No mods, so there are not many planets on insane. I realised I was quickly making alot of starbases when I decided to que up all the modules for the starbases on the starbase screen, so I double checked the shipyard it was full of construtors for starbases, but when the constructors were ejected they didn't automatically move. I thought they were going to move to the starbases what happened. If it's my fault tell me what I need to press to make this happen.
Ignore I guess if you are used to manually moving constructors you are not willing to let the constructors to move by themselves. The ship list is wonderful.