Problems with xelatex and arc in tikz

Problems with xelatex and arc in tikz

When I use \setdefaultlanguage{thai} and arc command, output not smooth.
How to set my xelatex code? I think this ploblem about thai scale, or not.
\documentclass{article}
\usepackage{polyglossia}
\setdefaultlanguage{thai}
\newfontfamily{\thaifont}{Microsoft Sans Serif}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw (0,0) arc (-120:175:1cm);
\end{tikzpicture}
\end{document}
Thanks.