Another alternator problem

Nothing is loose in or on the alternator. I put it back on the car and tested it again to see if something changed somehow.
When the car is at idle and my multimeter is hooked to the output stud of the alternator, the voltage sits at about 11.87 volts and slowly drops about .01 volt every 10 seconds. At about 4Krpm the voltage slowly rises about .01 volt every second.
I’m going to call Powermaster when they open back up tomorrow.