diff --git a/autotests/export/latex/ru-accent-ascii.lyx b/autotests/export/latex/ru-accent-ascii.lyx
new file mode 100644
index 0000000000..b91c8cbd21
--- /dev/null
+++ b/autotests/export/latex/ru-accent-ascii.lyx
@@ -0,0 +1,165 @@
+#LyX 2.3 created this file. For more info see http://www.lyx.org/
+\lyxformat 512
+\begin_document
+\begin_header
+\save_transient_properties true
+\origin unavailable
+\textclass article
+\begin_preamble
+% DO NOT ALTER THIS PREAMBLE!!! 
+%
+%This preamble is designed to ensure that the document prints
+% out as advertised. If you mess with this preamble,
+% parts of the document may not print out as expected. If you
+% have problems LaTeXing this file, please contact 
+% the documentation team
+% email: lyx-docs@lists.lyx.org
+
+% the pages of the TOC is numbered roman
+% and a pdf-bookmark for the TOC is added
+\pagenumbering{roman}
+\let\myTOC\tableofcontents
+\renewcommand\tableofcontents{%
+\pdfbookmark[1]{\contentsname}{}
+\myTOC
+\cleardoublepage
+\pagenumbering{arabic} }
+\end_preamble
+\use_default_options false
+\maintain_unincluded_children false
+\language russian
+\language_package default
+\inputencoding ascii
+\fontencoding global
+\font_roman "libertine" "DejaVu Serif"
+\font_sans "biolinum" "DejaVu Sans"
+\font_typewriter "libertine-mono" "DejaVu Sans Mono"
+\font_math "auto" "auto"
+\font_default_family default
+\use_non_tex_fonts false
+\font_sc false
+\font_osf false
+\font_sf_scale 100 100
+\font_tt_scale 100 100
+\use_microtype false
+\graphics default
+\default_output_format pdf2
+\output_sync 0
+\bibtex_command default
+\index_command default
+\paperfontsize 12
+\spacing single
+\use_hyperref false
+\pdf_title "Введение в LyX"
+\pdf_author "LyX Team"
+\pdf_subject "LyX-documentation Intro"
+\pdf_keywords "LyX, documentation"
+\pdf_bookmarks true
+\pdf_bookmarksnumbered true
+\pdf_bookmarksopen true
+\pdf_bookmarksopenlevel 2
+\pdf_breaklinks false
+\pdf_pdfborder false
+\pdf_colorlinks true
+\pdf_backref false
+\pdf_pdfusetitle false
+\pdf_quoted_options "linkcolor=black, citecolor=black, urlcolor=blue, filecolor=blue, pdfpagelayout=OneColumn, pdfnewwindow=true, pdfstartview=XYZ, plainpages=false"
+\papersize a4paper
+\use_geometry false
+\use_package amsmath 1
+\use_package amssymb 1
+\use_package cancel 0
+\use_package esint 0
+\use_package mathdots 1
+\use_package mathtools 0
+\use_package mhchem 1
+\use_package stackrel 0
+\use_package stmaryrd 0
+\use_package undertilde 0
+\cite_engine basic
+\cite_engine_type default
+\biblio_style plain
+\use_bibtopic false
+\use_indices false
+\paperorientation portrait
+\suppress_date false
+\justification false
+\use_refstyle 0
+\index Предметный указатель
+\shortcut idx
+\color #008000
+\end_index
+\secnumdepth 3
+\tocdepth 2
+\paragraph_separation indent
+\paragraph_indentation default
+\quotes_language french
+\papercolumns 1
+\papersides 1
+\paperpagestyle default
+\tracking_changes false
+\output_changes false
+\html_math_output 0
+\html_css_as_file 0
+\html_be_strict false
+\end_header
+
+\begin_body
+
+\begin_layout Standard
+Accented cyrillic characters fail if the input encoding is ASCII, both ERT
+\end_layout
+
+\begin_layout Quotation
+Вы узн
+\begin_inset ERT
+status collapsed
+
+\begin_layout Plain Layout
+
+
+\backslash
+'
+\end_layout
+
+\end_inset
+
+аете, как использовать LyX.
+\end_layout
+
+\begin_layout Standard
+and Combining chars
+\end_layout
+
+\begin_layout Quotation
+Вы узна́ете, как использовать LyX.
+\end_layout
+
+\begin_layout Standard
+This is due to bugs 
+\begin_inset Flex URL
+status open
+
+\begin_layout Plain Layout
+
+http://www.lyx.org/trac/ticket/9637
+\end_layout
+
+\end_inset
+
+ and 
+\begin_inset Flex URL
+status open
+
+\begin_layout Plain Layout
+
+http://www.lyx.org/trac/ticket/6463
+\end_layout
+
+\end_inset
+
+
+\end_layout
+
+\end_body
+\end_document
diff --git a/development/autotests/invertedTests b/development/autotests/invertedTests
index 11cc604152..4c000430f1 100644
--- a/development/autotests/invertedTests
+++ b/development/autotests/invertedTests
@@ -84,6 +84,10 @@ export/export/latex/LongestLabelWithUnderscore.*
 # if they contain non-ASCII characters)
 export/doc/(es|fr)/Additional_pdf4_texF
 
+#9637 textgreek and textcyr depend on font-encoding, not input encoding
+#6463 font encoding changes and combining accents
+# this leads to failure of ru/Intro with XeTeX (pdf4_texF)
+export/export/latex/ru-accent-ascii.*
 
 Sublabel: ert
 #