diff --git a/CHANGES b/CHANGES
index a6a0a213b1..c6da7d67ca 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,10 +3,15 @@
 			unexpected action could be taken. This has been
 			corrected. [RT #39481]
 
-4121.	[bug]		When updating a response-policy zone via AXFR,
-			summary data about other policy zones could fall
-			out of sync. Ultimately this could trigger an
-			assertion failure in rpz.c. [RT #39567]
+4121.	[bug]		On servers with one or more policy zones
+			configured as slaves, if a policy zone updated
+			during regular operation (rather than at
+			startup) using a full zone reload, such as via
+			AXFR, a bug could allow the RPZ summary data to
+			fall out of sync, potentially leading to an
+			assertion failure in rpz.c when further
+			incremental updates were made to the zone, such
+			as via IXFR. [RT #39567]
 
 4120.	[bug]		A bug in RPZ could cause the server to crash if
 			policy zones were updated while recursion was
diff --git a/doc/arm/notes.xml b/doc/arm/notes.xml
index 1da3580dd7..22c2019027 100644
--- a/doc/arm/notes.xml
+++ b/doc/arm/notes.xml
@@ -152,12 +152,13 @@
 	</listitem>
 	<listitem>
 	  <para>
-	    On servers with more than one policy zone configured,
-	    if one policy zone was updated via AXFR (especially when
-	    the zone was very large) a race condition could allow the
-	    RPZ summary data to fall out of sync with the policy zones,
-	    potentially leading to an assertion failure in rpz.c.
-	    [RT #39567]
+	    On servers with one or more policy zones configured as
+	    slaves, if a policy zone updated during regular operation
+	    (rather than at startup) using a full zone reload, such as
+	    via AXFR, a bug could allow the RPZ summary data to fall out
+	    of sync, potentially leading to an assertion failure in
+	    rpz.c when further incremental updates were made to the
+	    zone, such as via IXFR. [RT #39567]
 	  </para>
 	</listitem>
 	<listitem>