The Mac Observer on the iTunes 11.2 upgrade causing the ’/Users` folder invisible:

Apple’s QA process should have caught this. How can an engineer test the installation of a new version of iTunes and not test all the related areas? That is, users may not be aware of the impact of having Find My Mac (FMM) turned on, but OS engineers are expected to be aware of secondary effects via their expertise.

Yes, and no. It all depends on where you assign your resources. Right now they’re all busy testing iOS 8 and OS X 10.10. No QA process is perfect, and you cannot test everything.