What else to try to fix this bug or does MS needs to fix this bug?
The fact that it is not generally reproducible makes it hard to fix. I suspect any problem report opened with just the description we have so far would just be closed: no repro.
FWIW thinking that it might be a problem with account class I just started my Guest account and it worked as expected, e.g. once Show admin tools was turned on both msc and sy co worked as searches for msconfig.exe
Is there anything else about your install that you can think of which could account for your discrepancy?
I just realized that you probably installed an ISO and what I am using is whatever update the Store gives me. So that might be one. What if we compared by the first two lines of msinfo32.exe System Summary?
OS Name Microsoft Windows 8.1 Pro Preview
Version 6.3.9431 Build 9431
BTW I figured out a wmic query to get the version but not the OS Name, so this less elegant method will have to do for now. ; )