[O] Bug: CUSTOM_ID property not used in LaTeX-Export [9.1.9 (release_9.1.9-65-g5e4542 @ /usr/share/emacs/27.0.50/lisp/org/)]

[beckonsmorbid]

Emacs  : GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.29)
 of 2018-04-05
Package: Org mode version 9.1.9 (release_9.1.9-65-g5e4542 @
/usr/share/emacs/27.0.50/lisp/org/)

----------------------------------------------------------------------------------------------
Hi,

It seems the CUSTOM_ID property isn't being used in the
Latex-export, for example this org file:

#+BEGIN_SRC org
  ,* foo
    :PROPERTIES:
    :CUSTOM_ID: sec:foo
    :END:
  ,* bar
    :PROPERTIES:
    :CUSTOM_ID: sec:bar
    :END:
  \ref{sec:foo}
  \ref{sec:bar}
#+END_SRC

gets exported to this Latex code:

#+BEGIN_SRC latex
% Created 2018-04-06 Fr 10:19
% Intended LaTeX compiler: pdflatex
\documentclass[11pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{graphicx}
\usepackage{grffile}
\usepackage{longtable}
\usepackage{wrapfig}
\usepackage{rotating}
\usepackage[normalem]{ulem}
\usepackage{amsmath}
\usepackage{textcomp}
\usepackage{amssymb}
\usepackage{capt-of}
\usepackage{hyperref}
\date{\today}
\title{}
\hypersetup{
 pdfauthor={},
 pdftitle={},
 pdfkeywords={},
 pdfsubject={},
 pdfcreator={Emacs 27.0.50 (Org mode 9.1.9)},
 pdflang={English}}
\begin{document}

\tableofcontents

\section{foo}
\label{sec:org6f6b527}
\section{bar}
\label{sec:org9cbe09f}
\ref{sec:foo}
\ref{sec:bar}
\end{document}
#+END_SRC
which breaks the \ref-links.
This is in the default config with emacs -Q.

Thanks for your help and all the work on org,
Simon