diff --git a/ci/test-documentation.sh b/ci/test-documentation.sh
index 8f91f48c81..d49089832d 100755
--- a/ci/test-documentation.sh
+++ b/ci/test-documentation.sh
@@ -5,29 +5,38 @@
 
 . ${0%/*}/lib.sh
 
+filter_log () {
+	sed -e '/^GIT_VERSION = /d' \
+	    -e '/^    \* new asciidoc flags$/d' \
+	    "$1"
+}
+
 make check-builtins
 make check-docs
 
 # Build docs with AsciiDoc
-make doc > >(tee stdout.log) 2> >(tee stderr.log >&2)
-! test -s stderr.log
+make doc > >(tee stdout.log) 2> >(tee stderr.raw >&2)
+cat stderr.raw
+filter_log stderr.raw >stderr.log
+test ! -s stderr.log
 test -s Documentation/git.html
 test -s Documentation/git.xml
 test -s Documentation/git.1
 grep '<meta name="generator" content="AsciiDoc ' Documentation/git.html
 
-rm -f stdout.log stderr.log
+rm -f stdout.log stderr.log stderr.raw
 check_unignored_build_artifacts
 
 # Build docs with AsciiDoctor
 make clean
-make USE_ASCIIDOCTOR=1 doc > >(tee stdout.log) 2> >(tee stderr.log >&2)
-sed '/^GIT_VERSION = / d' stderr.log
-! test -s stderr.log
+make USE_ASCIIDOCTOR=1 doc > >(tee stdout.log) 2> >(tee stderr.raw >&2)
+cat stderr.raw
+filter_log stderr.raw >stderr.log
+test ! -s stderr.log
 test -s Documentation/git.html
 grep '<meta name="generator" content="Asciidoctor ' Documentation/git.html
 
-rm -f stdout.log stderr.log
+rm -f stdout.log stderr.log stderr.raw
 check_unignored_build_artifacts
 
 save_good_tree