Let's run this snippet with xelatex:
\documentclass{article}
\usepackage{fontspec}
\usepackage{xeCJK}
\setCJKmainfont{Source Han Serif SC} % SimSun is OK
\begin{document}
见
\end{document}
The document body is a single Chinese character, 见 (U+89C1). Using the font Source Han Serif SC, the generated PDF contains another character ⻅ (U+2EC5). Using SimSun, the generated PDF contains the original 见 (U+89C1).
Could anyone tell me who is to blame: fontspec, xeCJK, or Source Han Serif SC; and how to stick to the original character in all cases? Thanks.
\showoutputwhich character does it show in the log? – David Carlisle Oct 12 '18 at 08:19\setmainfontyou should be able to compare with lualatex, what happens there... – David Carlisle Oct 12 '18 at 08:45