I'm playing the 1.3 betaX, gigantic galaxy. My territory includes the most economic resources I've yet seen clustered together: 6 mines all within one to three sectors of my homeworld.
It looked odd, but I thought about what some folks have posted about paying your way through a lack of morale, research, etc., and thought I'd give it a try. Things were fine for many turns after I got all the mines running at +44.
But then something changed, and I'm not sure whether it was me beginning to deploy Extraction Centers to get +56 out of the mines. Whatever the cause, my economy started showing huge dips down to about 20% of what I'd come to think of as "normal."
So far, I've had a few of these downturns followed by a roughly equal stretch of time with revenues at "normal" levels. The AI players have shown no drops, so I don't think it was a Galactic Depression event that didn't get announced. There is an active event (Xenophobia), but I can't see how that would affect my economy (no tourism money to speak of).
Any guesses as to what's going on?