Last month, Cerberus Corporation recieved approximately 2 million in income from its facilities. This month, we barely recieved 2 hundred thousand. All facilities are powered, all option set, and operator is active. Unless something has been changed in the equations, I would have expected to have gotten more, since we have built new structures since last month. Could this be a bug, or just a bad month?
The equation hasn't changed, I'm sure that you messed up in some way but I'm also sure you'll insist it wasn't you and must be a bug like people continue to bother the admin with every month even when it worked fine for everyone else.
If you've been building did you take into consideration the effect those facilities have on the planet stats? none of the cities became unpowered whilst they wait for new powergens to finish to meet the greater demands of more facilities?
From my experience with facility income, it is doubtful that a change in operator, even if going from level 5 to level 1 or 0, could explain such an enormous drop in income.
Basically, I'd look at what Ralgarrch said and maybe also see if all the facilities provided income. If you have (for example) ten facilities that made 50k each last month, only making 5k this month, then stats and/or operator are to blame.
Though if the drop in income related was because only a handful of buildings made cash, then it probably relates to something else (like the facility being set open to all or not, though seems you say that was not the issue).
Check the facility income transaction sheet to see how many facilities gave you income last month and how many gave income this month. What's the planet's morale, crime and employment ratings?