Twice now, I'm taken my empire from the following situation:
33% military
33% production
33% research
net income: a few bc
to...
0% military
50% production
50% research
net income: hundreds of BCs
so I turn my industrial capacity slider all the way up to 100%...
net income: less, but still hundreds of BCs
but...
The next turn, all of the sudden, I'm losing money hand over fist. So I go back to the economy screen and it reads...
0% military
50% research
50% production
net income: negative hundreds of BCs
...so I have to move my industrial capacity back down, say, to 75% so that I have a net income of 0BC.
The point is here that, at the point where I changed my military to 0%, it seems to lie about my net income. (Which, in my case, causes me to make further changes which makes this even worse.)