The issue was reported here:
https://www.mail-archive.com/search?l=mid&q=
20221211202917.f6py2kmrcdxtwaps%40gary
# https://www.mail-archive.com/search?l=mid&q=20200915233446.atwbyulny5gsbtyi%40tallinn
export/examples/ru/Presentations/Beamer_lyx(16|20)
+# lyx2lyx bug in lyx_2_4.py that is triggered in the Russian User Guide
+# for some reason.
+# https://www.mail-archive.com/search?l=mid&q=20221211202917.f6py2kmrcdxtwaps%40gary
+export/doc/ru/UserGuide_lyx(16|20|21|22|23)
+
# ==============================================================
Sublabel: ert