Playing as the Iridium on an immense map, tried to que some factories on my planet and they didn't show up. In attempting to build them I managed to que about 12 factories in the build list, on about six slots on my planet. Every time i tried to add a factory it added it to the que but not on the planet screen itself. When I left the planet screen and went back the factories appeared on the planet in the six slots i attempted, but still showed about 12 in the queue. I'm not sure if it will count the ghost factories towards my production, if so, unlimited factories on a planet is one heck of an exploit.