diff --git a/bin/tests/system/synthfromdnssec/ns2/named.conf.in b/bin/tests/system/synthfromdnssec/ns2/named.conf.in
index 736d428172..cc303072a2 100644
--- a/bin/tests/system/synthfromdnssec/ns2/named.conf.in
+++ b/bin/tests/system/synthfromdnssec/ns2/named.conf.in
@@ -49,4 +49,9 @@ zone "example.internal" {
 	file "example.internal.db";
 };
 
+zone "example.internal2" {
+	type primary;
+	file "example.internal.db";
+};
+
 include "../ns1/trusted.conf";
diff --git a/bin/tests/system/synthfromdnssec/ns5/internal2.db b/bin/tests/system/synthfromdnssec/ns5/internal2.db
new file mode 100644
index 0000000000..4f07f700d6
--- /dev/null
+++ b/bin/tests/system/synthfromdnssec/ns5/internal2.db
@@ -0,0 +1,17 @@
+; Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+;
+; SPDX-License-Identifier: MPL-2.0
+;
+; This Source Code Form is subject to the terms of the Mozilla Public
+; License, v. 2.0.  If a copy of the MPL was not distributed with this
+; file, you can obtain one at https://mozilla.org/MPL/2.0/.
+;
+; See the COPYRIGHT file distributed with this work for additional
+; information regarding copyright ownership.
+
+$TTL 3600
+@		SOA	ns5 hostmaster 1 3600 1200 604800 3600
+@		NS	ns5
+ns5		A	10.53.0.5
+example		NS	ns2.example
+ns2.example	A	10.53.0.2
diff --git a/bin/tests/system/synthfromdnssec/ns5/named.conf.in b/bin/tests/system/synthfromdnssec/ns5/named.conf.in
index a98ef39ddf..885708c767 100644
--- a/bin/tests/system/synthfromdnssec/ns5/named.conf.in
+++ b/bin/tests/system/synthfromdnssec/ns5/named.conf.in
@@ -52,4 +52,9 @@ zone "example.internal" {
 	forwarders { 10.53.0.2; };
 };
 
+zone "internal2" {
+	type primary;
+	file "internal2.db";
+};
+
 include "../ns1/trusted.conf";
diff --git a/bin/tests/system/synthfromdnssec/tests.sh b/bin/tests/system/synthfromdnssec/tests.sh
index f5383c97e2..aee907e2e0 100644
--- a/bin/tests/system/synthfromdnssec/tests.sh
+++ b/bin/tests/system/synthfromdnssec/tests.sh
@@ -884,5 +884,19 @@ n=$((n+1))
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=$((status+ret))
 
+echo_i "check synth-from-dnssec with grafted zone (primary zone) ($n)"
+ret=0
+#prime cache with NXDOMAIN NSEC covering 'fun' to 'minimal'
+dig_with_opts internal @10.53.0.5 > dig.out.ns5-1.test$n || ret=1
+grep "status: NXDOMAIN" dig.out.ns5-1.test$n >/dev/null || ret=1
+grep '^fun\..*NSEC.minimal\. ' dig.out.ns5-1.test$n >/dev/null || ret=1
+#perform lookup in grafted zone
+dig_with_opts example.internal2 @10.53.0.5 > dig.out.ns5-2.test$n || ret=1
+grep "status: NOERROR" dig.out.ns5-2.test$n >/dev/null || ret=1
+grep '^example\.internal2\..*A.1.2.3.4$' dig.out.ns5-2.test$n >/dev/null || ret=1
+n=$((n+1))
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=$((status+ret))
+
 echo_i "exit status: $status"
 [ $status -eq 0 ] || exit 1