Named destination that are created by hypertarget{AnchorLabel}{AnchorText} or \hyperdef{category}{label}{} are broken in newer XeTeX versions (e.g. 3.14159265-2.6-0.99996 (MiKTeX 2.9 64-bit) and 3.14159265-2.6-0.99992 (TeX Live 2015/dev/Debian)). When using pdflatex in the current MiKTeX distribution everything works as expected.
The problem can be solved by editing the configuration file dvipdfmx.cfg and adding there the line
C 0x0010
after the "Dvipdfmx Compatibility Flags" block (see Solution on StackExchage).
I reported this bug to the XeTeX-Maintainers but the answer was that nothing can be done at the XeTeX end - the configuration update is to be done in MiKTeX and TeX Live distributions.
Here is the MWE (See also StackExchange posts 330342 and 275739:
\documentclass[]{scrreprt}
\usepackage[pdfencoding=auto]{hyperref}
\begin{document}
\chapter[First chapter - short title]{First chapter - long title}
\hypertarget{TestA}{AAA}
Some text
\clearpage
\section[First Section]{First Section - long title}
\hypertarget{TestB}{BBB}
Some further text
\clearpage
\subsection[A subsection - short title]{A subsection - long title}
\hypertarget{TestC}{CCC}
Some more text
\end{document}
Try to open resulting pdf with e.g.
Call "C:\Program Files (x86)\Adobe\Acrobat Reader DC\Reader\AcroRd32.exe" /a "nameddest=TestC" "C:\path\to\file.pdf"
or
CALL "C:\Program Files (x86)\SumatraPDF\SumatraPDF.exe" -nameddest TestC "C:\path\to\file.pdf"
The file should be opened at the last page.
MiKTeX now installs the modified
dvipdfm.cfg(lineC 0x0010added).Thank you!