diff --git a/development/autotests/invertedTests b/development/autotests/invertedTests
index 933cfba0b3..518c85469a 100644
--- a/development/autotests/invertedTests
+++ b/development/autotests/invertedTests
@@ -328,6 +328,16 @@ Sublabel: externalissues
 # https://www.mail-archive.com/search?l=mid&q=1506851183.3130.15.camel%40lyx.org
 export/examples/ja/lilypond_pdf
 
+# ps2pdf gives the following error on updated TL18:
+#   Error: /undefined in d7Z
+# For previous TL versions, there is no error but the output is incorrect
+# (jibberish instead of Japanese characters).
+export/examples/ja/UserGuide_pdf
+# Simliar situation for this document, with the following error:
+#   Error: /undefined in =52+WsoG&
+export/examples/ja/Additional_pdf
+
+
 
 # ======================================================================
 Sublabel: attic