That bug was there at the very beginning of the game and eventually got fixed. But I noticed there's still an exploit left open.
See ticket #ISZ-865-90245
Create a shipyard sponsored by 5 planets.
If you colonize another existing planet in the same system as your shipyard, it won't be added to the shipyard sponsors, as it should be.
However, if you use an artifact like Klin of Worlds to create a new class 5 planet, then colonize it, that new colony will be added as 6th, 7th, 8th... sponsor to your shipyard.
I haven't played far enough in Benevolent ideology to see if it does the same thing when you get a new class 10 or 16 planet in your home system, but I suspect it is a possibility that could need to be investigated. If anyone here is playing with that line of benevolent ideology and could test it, please report here for the devs to see.
Yes, I know, it's a voluntary exploit, I don't have to do it, so it's a minor bug it doesn't break the gameplay, but it would still be nice if that exploit were fixed. I suppose some people still play this game in MP and it could unbalance things a little for them.