The more I read into recent AHC issues, the less sense it all makes to me. Amazing that with those new components, including the pump, that the dealer can't get this corrected. As you said, it really makes you wonder just what is happening with these AHC system maintenance repair failures as of recent. I'm honestly debating trying to ride on the original AHC fluid now. I'm just shy of 100k miles on the original fluid, but I question is it even worth trying to do this maintenance item given the headache others are experiencing.
This almost reminds me of the mid-90's turbo car era where all the dealerships had about 1-2 gurus that truly understood the vehicles and their quirks (prior to the modification tuning world we live in now), but everyone else at the dealer seemed to do more harm than good when they tried repairs.