complexity to fix):
Report : https://www.mail-archive.com/search?l=mid&q=20210125200655.e27xaaoy2belyxhw%40tallinn
+Report : https://www.mail-archive.com/lyx-devel@lists.lyx.org/msg218248.html
Testing compilation after lyx2lyx roundtrip was not helpful in this case:
report : https://www.mail-archive.com/lyx-devel@lists.lyx.org/msg218232.html
Fix : b8502a3e, e316e21a
ctests : de/UserGuide_lyx(16|20|21)
+report : https://www.mail-archive.com/search?l=mid&q=20221218210348.gkwloeu74zjewqsu%40gary
+Fix : c2a324e24
+ctests : DEFAULTOUTPUT_export/export/latex/CJK/zh_CN-en-de-el-ru_language-default_pdf2