diff --git a/src/doc/common/custom-sphinx-build.py b/src/doc/common/custom-sphinx-build.py
index 8cdfcd4029f..0f59de9229a 100644
--- a/src/doc/common/custom-sphinx-build.py
+++ b/src/doc/common/custom-sphinx-build.py
@@ -49,7 +49,6 @@ def term_width_line(text):
 
 # warnings: regular expressions (or strings) indicating a problem with
 # docbuilding. Raise an exception if any of these occur.
-
 warnings = (re.compile('Segmentation fault'),
             re.compile('SEVERE'),
             re.compile('ERROR'),
@@ -57,8 +56,17 @@ def term_width_line(text):
             re.compile('Exception occurred'),
             re.compile('Sphinx error'))
 
+# We want all warnings to actually be errors.
+# Exceptions:
+# - warnings upon building the LaTeX documentation
+# - undefined labels upon the first pass of the compilation: some
+#   cross links may legitimately not yet be resolvable at this point.
 if 'latex' not in sys.argv:
-    warnings += (re.compile('WARNING'),)
+    if 'multidoc_first_pass=1' in sys.argv:
+        # Catch all warnings except 'WARNING: undefined label'
+        warnings += (re.compile('WARNING: (?!undefined label)'),)
+    else:
+        warnings += (re.compile('WARNING:'),)
 
 
 # Do not error out at the first warning, sometimes there is more
diff --git a/src/doc/en/reference/dynamics/index.rst b/src/doc/en/reference/dynamics/index.rst
index 002577d9be5..3ded1bba00b 100644
--- a/src/doc/en/reference/dynamics/index.rst
+++ b/src/doc/en/reference/dynamics/index.rst
@@ -7,4 +7,8 @@ Discrete dynamics
    interval_exchanges
    flat_surfaces
 
+.. SEEALSO::
+
+    - :ref:`sage.combinat.e_one_star`
+
 .. include:: ../footer.txt