New erroneous behavior after installation of l3packages, etc

Hello,

The MikTeX updater recently removed the obsolete packages expl3 and 
xpackages. The new packages l3packages and l3kernel were installed to 
replace them.

Now, I am getting entirely new an unexpected behavior from fontspec.sty. 
Running XeLaTeX on a simple file:

    \documentclass[12pt]{article}
    \usepackage{fontspec}
    \usepackage{xunicode}
    \usepackage{xltxtra}
    \setmainfont{MinionPro-Regular}
    \begin{document}
    \textsc{Small Capitals}
    \end{document}

now produces this error:

      Font shape `EU1/MinionPro-Regular(0)/m/sc' undefined
      using `EU1/MinionPro-Regular(0)/m/n' instead on input line [...]

(Yes, Minion Pro does have a set of true small caps)

Everything was working as expected until the removal and update of the 
LaTeX3 packages. I have been using XeLaTeX with OpenType fonts for a long 
time now and have never experienced these problems.

I have not made any other changes to my MikTeX installation.

Has anyone else experienced this problem?

Best,
Anshu



------------------------------------------------------------------------------
All of the data generated in your IT infrastructure is seriously valuable.
Why? It contains a definitive record of application performance, security 
threats, fraudulent activity, and more. Splunk takes this data and makes 
sense of it. IT sense. And common sense.
http://p.sf.net/sfu/splunk-d2d-c2