diff --git a/docs/guides/alias.rst b/docs/guides/alias.rst
index 48c74bd65c46..ff73fbc5d4b0 100644
--- a/docs/guides/alias.rst
+++ b/docs/guides/alias.rst
@@ -49,6 +49,8 @@ When set to 'yes', PowerDNS will look up the A and AAAA records of the name in t
 This is useful when your secondary servers do not understand ALIAS, or should not look up the addresses themselves.
 Note that secondaries will not automatically follow changes in those A/AAAA records unless you AXFR regularly.
 
+If secondaries are operated with nameserver software which is not capable of synthesising ALIAS records the zone will probably go out of sync. Because updated ALIAS target records will not result in an increment of the Serial, which means that Secondaries won't pull the Zone.
+
 If the ALIAS target cannot be resolved, the AXFR will fail.
 When set to 'ignore-errors', an unresolvable ALIAS target will be omitted from the outgoing transfer.