Slipped my radar, but here is a patch for
https://fedorahosted.org/sssd/ticket/2683
diff --git a/src/man/sssd.conf.5.xml b/src/man/sssd.conf.5.xml
index 573f421..c17e8c4 100644
--- a/src/man/sssd.conf.5.xml
+++ b/src/man/sssd.conf.5.xml
@@ -509,6 +509,10 @@ subdomain_inherit = ldap_purge_cache_timeout
<para>
Default: none
</para>
+ <para>
+ Note: This option only works with the ipa provider
+ and AD trust setup.
+ </para>
</listitem>
</varlistentry>
</variablelist>