I recently went through the trouble of maxing out the luck and relevant SPECIAL of all my dwellers in Fallout shelter. My vault has around 160 some odd dwellers and all of my rooms have dwellers with a SPECIAL for that room of 10 and luck of 10. For example, my gardens all have dwellers with a (natural) Agility of 10 and a luck of 10. Since doing this I've noticed I hardly ever receive cap rewards anymore. I used to be able to make thousands after a few rounds of collections over the course of five minutes. Now I make nothing.
So what are the factors for the caps reward algorithm? Did I screw something up by maxing out either luck or the room's SPECIAL?