That’s probably a question best answered by level 2/3 Support Engineer or Product Development. Level 1 support didn't know why it happens, they just know the fix and told me it randomly happens, at the time they did not know why. I would assume there are multiple factors, group policy user rights assignments, restrictions, UAC not properly disabled, custom registry imports/settings which affect the install, low bandwidth on install download, bad checksum on download that’s not error’ing out, etc… Hard for a company to plan for every possible windows install scenario.
I've setup and configured 7.1 ~15 times for multiple companies and I’ve never seen this in 7.1 on any SP release.
I actually thought this would have been resolved in the Activity Center HF1, but after installing that I had to go back and do what @ jpopik did.
I am actually thinking it is something with our group policy settings affecting the installation. This happened on our Parent NS in out MGMT domain (PCI/HIPPA/NIST compliant), and on the Child NS in our Imaging domain (PCI/HIPPA compliant), but did not happen on the Child NS in our Corporate Domain (which the Corporate domain has a completely different set of domain and computer policies managed by the Corp Teams).
It's an easy workaround so I have not looked too much into it.