*face palms* dsicovered this today, and the cause. Thought it might have been a buggy growth-rate bonus calculation thing...
ended up with a sol system under 200k (modded to 375.)
Had a system with 675, before moons. Thank God I did hold off!
I also tried to mod in a table for "MoonGrowthRate" . No joy. *scratches head* It didn't hurt to try. But someone else probably tried that (and didn't tell anyone)