diff --git a/src/calibre/library/catalogs/epub_mobi_builder.py b/src/calibre/library/catalogs/epub_mobi_builder.py
index 04116cb0e3..62f94aedc4 100644
--- a/src/calibre/library/catalogs/epub_mobi_builder.py
+++ b/src/calibre/library/catalogs/epub_mobi_builder.py
@@ -706,6 +706,8 @@ class CatalogBuilder(object):
                     if last_c in exceptions.keys():
                         last_c = exceptions[unicode(last_c)]
                     last_ordnum = ordnum
+                else:
+                    last_c = cl_list[idx-1]
                 cl_list[idx] = last_c
 
         if self.DEBUG and self.opts.verbose: