Updating MiKTeX: again errors

Question

After today's update of MiKTeX I got lot of errors like this:

! \textfont 192 is undefined (character ???).
\beamer@doifinframe ...v 10^{13}\;\text {cm}^{-3}$
                                                   is rated as high for heli...
l.345 \end{frame}

? h
Somewhere in the math formula just ended, you used the
stated character from an undefined font family. For example,
plain TeX doesn't allow \it or \sl in subscripts. Proceed,
and I'll try to forget that I needed that character.

Such errors occur when I use xelatex to compile my documents. Initially I've got such errors for beamer class but latter I found similar errors for revtex class. Here is typical font settings for my docs:

\usepackage[math-style=ISO,bold-style=ISO]{unicode-math}
%\setmathfont[version=lm,Color=660000]{Latin Modern Math}
%\setmathfont[version=asana,Color=000000]{Asana Math}% <== мой выбор
%\setmathfont[version=xits,Color=000000]{XITS Math}
\setmathfont[version=cambria,Color=000066]{Cambria Math}
%\setmathfont[version=cambria]{Cambria Math}

%\mathversion{lm} % не показывает \vec{\bm\varkappa}
%\mathversion{xits}
%\mathversion{asana}
\mathversion{cambria}

I tried various fonts with the same result. The errors occur in math formulas but a compiled document looks fine. None errors occur if I use pdflatex instead of xelatex. Fortunately, I have TeX Live 2013 (which I have not updated) and it works fine.

Can someone tell me what to do with these errors?

UPDATE: MWE:

% !Mode:: TeX:UTF-8
\documentclass{article}
\usepackage{ifxetex}
\ifxetex
    \usepackage{unicode-math}
    \setmathfont{Cambria Math}
\fi
\begin{document}
    $$
      \varepsilon_{-}
    $$

    $$
      =\varepsilon_{l}
    $$
\end{document}