diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index bc6d8246a7..0e68670767 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -391,10 +391,13 @@ slot_modify_cstrings(TupleTableSlot *slot, LogicalRepRelMapEntry *rel,
 		Form_pg_attribute att = TupleDescAttr(slot->tts_tupleDescriptor, i);
 		int			remoteattnum = rel->attrmap[i];
 
-		if (remoteattnum >= 0 && !replaces[remoteattnum])
+		if (remoteattnum < 0)
 			continue;
 
-		if (remoteattnum >= 0 && values[remoteattnum] != NULL)
+		if (!replaces[remoteattnum])
+			continue;
+
+		if (values[remoteattnum] != NULL)
 		{
 			Oid			typinput;
 			Oid			typioparam;
diff --git a/src/test/subscription/t/008_diff_schema.pl b/src/test/subscription/t/008_diff_schema.pl
new file mode 100644
index 0000000000..b71be6e487
--- /dev/null
+++ b/src/test/subscription/t/008_diff_schema.pl
@@ -0,0 +1,80 @@
+# Test behavior with different schema on subscriber
+use strict;
+use warnings;
+use PostgresNode;
+use TestLib;
+use Test::More tests => 3;
+
+sub wait_for_caught_up
+{
+	my ($node, $appname) = @_;
+
+	$node->poll_query_until('postgres',
+"SELECT pg_current_wal_lsn() <= replay_lsn FROM pg_stat_replication WHERE application_name = '$appname';"
+	) or die "Timed out while waiting for subscriber to catch up";
+}
+
+# Create publisher node
+my $node_publisher = get_new_node('publisher');
+$node_publisher->init(allows_streaming => 'logical');
+$node_publisher->start;
+
+# Create subscriber node
+my $node_subscriber = get_new_node('subscriber');
+$node_subscriber->init(allows_streaming => 'logical');
+$node_subscriber->start;
+
+# Create some preexisting content on publisher
+$node_publisher->safe_psql('postgres',
+	"CREATE TABLE test_tab (a int primary key, b varchar)");
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO test_tab VALUES (1, 'foo'), (2, 'bar')");
+
+# Setup structure on subscriber
+$node_subscriber->safe_psql('postgres', "CREATE TABLE test_tab (a int primary key, b text, c timestamptz DEFAULT now(), d bigint DEFAULT 999)");
+
+# Setup logical replication
+my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
+$node_publisher->safe_psql('postgres', "CREATE PUBLICATION tap_pub FOR TABLE test_tab");
+
+my $appname = 'tap_sub';
+$node_subscriber->safe_psql('postgres',
+"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub"
+);
+
+wait_for_caught_up($node_publisher, $appname);
+
+# Also wait for initial table sync to finish
+my $synced_query =
+"SELECT count(1) = 0 FROM pg_subscription_rel WHERE srsubstate NOT IN ('r', 's');";
+$node_subscriber->poll_query_until('postgres', $synced_query)
+  or die "Timed out while waiting for subscriber to synchronize data";
+
+my $result =
+  $node_subscriber->safe_psql('postgres', "SELECT count(*), count(c), count(d = 999) FROM test_tab");
+is($result, qq(2|2|2), 'check initial data was copied to subscriber');
+
+# Update the rows on the publisher and check the additional columns on
+# subscriber didn't change
+$node_publisher->safe_psql('postgres', "UPDATE test_tab SET b = md5(b)");
+
+wait_for_caught_up($node_publisher, $appname);
+
+$result =
+  $node_subscriber->safe_psql('postgres', "SELECT count(*), count(c), count(d = 999) FROM test_tab");
+is($result, qq(2|2|2), 'check extra columns contain local defaults');
+
+# Change the local values of the extra columns on the subscriber,
+# update publisher, and check that subscriber retains the expected
+# values
+$node_subscriber->safe_psql('postgres', "UPDATE test_tab SET c = 'epoch'::timestamptz + 987654321 * interval '1s'");
+$node_publisher->safe_psql('postgres', "UPDATE test_tab SET b = md5(a::text)");
+
+wait_for_caught_up($node_publisher, $appname);
+
+$result =
+  $node_subscriber->safe_psql('postgres', "SELECT count(*), count(extract(epoch from c) = 987654321), count(d = 999) FROM test_tab");
+is($result, qq(2|2|2), 'check extra columns contain locally changed data');
+
+$node_subscriber->stop;
+$node_publisher->stop;