A pretty minor one, but if you have a bunch of construction units and a small number of ruined installations to recover on a planet, you can get more recoveries than you have available installations. It seems to roll for all construction units first, and even though it will say that the ruins are fully exploited, it'll keep giving you more stuff after that.
In my case, I was doing some testing that happened to involve 102 construction units on a planet with 8 ruins. At the next construction phase, it showed me 8 "Factory Restored" events, a "Ruins Exploited" event, and then six more "Factory Restored" events after that. And it wasn't just cosmetic, the rewards did show up on the planet. (Each of those units was 1x INF-HQ2000 + 6x VEH-2xCON, if that matters.)