My replay on 27/12/2018 starting at 18.33.
I get to 1hr 10 mins into the game and send some asf to fight against an opponents gunships attacking my top island. Going into that attack I have a mass income hovering around +4000 with a surpus hovering around +1000.
I shoot them all down and send my asf back to patrol my base. They start landing at my air staging facilities for repairs and my mass income evaporates. It drops to about -2000 per tick and stays that way for the rest of the game. I can only get it back up by turning everything making something off and then it only goes to about +800 mass income.
My mass income only fully returns to normal when an opponent destroys my air staging facilities some time later and by then I lose as my production basically ceased until that point.