That may not be as silly as it sounds. When last at the parts store we were going through a rash of alts with the one way clutches in them, making noise of all sorts. The aftermarket does not have that issue pinned down yet, MANY alts with those clutches came back and I mean time and time again. Enough that customer eventually got all cash back and went elsewhere to buy them. Over and over. An '07 could easily have that clutch in it. Noise alone if bad enough was legitimate reason to warranty a part that may otherwise appear to be good. It means the clutch is not working correctly and alt testing machine does nothing to check for that.
The clutch by virtue of what it is is all brand new, you can't rebuild them in and of themselves. I am coming to the conclusion that a different value of spring or damping in belt tensioner can have an affect there, if tensioner was changed. The tensioner can set up in harmonic vibrations in the arm swing that aggravate the settling back in of the alt clutch to 100% full lock and drive. If clutch is constantly banging on/off lock/unlock due to a certain harmonic, that noise could easily be a whine of some sort. More fun brought to you by those who want to take old school alts and having turned them from $40 parts into $150 ones are now looking to add $50 with the clutches now. They have to simply to cover all the rejects. Our vendor said at one time the warranty issues with the clutches were going to bankrupt them. $200 for a modern alt ain't spit, that alt will cost $450 from Ford if a cent. All that to get a clutch that works, like the hydraulic motor mount issues these cars have that no one else can make parts correctly for..............
Whoever supplies the original part warranty will supply a replacement part but NEVER pays for the shop to re-install it, it says that on almost every piece of paperwork you will ever get on any new or rebuild part. At least here in Texas. Why the shops try to pick good lines, they eat the extra work if new part is bad. If client is big enough, supplier may choose here or there to help them out of course based on how strained or valued the relationship may be there. If shop could get free replacement labor from part maker then so could the guy on the street, try that here and they'll laugh you right out of the store.