Thunderbrd
C2C War Dog
That's exactly what is happening. When you exceed a particular number you basically have an irrecoverably bugged game. It will infect a lot more than just gold and research.I've found also that if you take over the world and get to the Galactic Era, then funny things start happening with gold and research, as though some kind of overflow bug is being triggered. I don't think it's my fault, except insofar as I added more content to get into overflow territory, and I don't know what to do about it or if some kind of computational bug is causing you problems.
I'm going to have to take some time soon to work on solving this issue... or get some help with it perhaps.