diff --git a/poky/documentation/migration-guides/migration-3.4.rst b/poky/documentation/migration-guides/migration-3.4.rst
index 6fa1ab2..e83e936 100644
--- a/poky/documentation/migration-guides/migration-3.4.rst
+++ b/poky/documentation/migration-guides/migration-3.4.rst
@@ -56,6 +56,13 @@
 case where some code does use them as overrides but some does not. We plan to try
 and make the tune code use overrides more consistently in the future.
 
+There are some variables which do not use override syntax which include the
+suffix to variables in ``layer.conf`` files such as :term:`BBFILE_PATTERN`,
+:term:`SRCREV`\ ``_xxx`` where ``xxx`` is a name from :term:`SRC_URI` and
+:term:`PREFERRED_VERSION`\ ``_xxx``. In particular, ``layer.conf`` suffixes
+may be the same as a :term:`DISTRO` override causing some confusion. We do
+plan to try and improve consistency as these issues are identified.
+
 To help with migration of layers there is a script in OE-Core. Once configured
 with the overrides used by a layer, this can be run as::