diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index 935212652c55e..928d6513f9eaf 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -4892,7 +4892,7 @@ function is_object_in_term( $object_id, $taxonomy, $terms = null ) {
 			return $object_terms;
 		}
 
-		wp_cache_set( $object_id, wp_list_pluck( $object_terms, 'term_id' ), "{$taxonomy}_relationships" );
+		wp_cache_add( $object_id, wp_list_pluck( $object_terms, 'term_id' ), "{$taxonomy}_relationships" );
 	}
 
 	if ( is_wp_error( $object_terms ) ) {
diff --git a/tests/phpunit/tests/term/isObjectInTerm.php b/tests/phpunit/tests/term/isObjectInTerm.php
index fbaf7e17767c8..6bd04a453e78e 100644
--- a/tests/phpunit/tests/term/isObjectInTerm.php
+++ b/tests/phpunit/tests/term/isObjectInTerm.php
@@ -179,4 +179,32 @@ public function test_should_not_be_fooled_by_a_stale_relationship_cache() {
 	public function test_invalid_taxonomy_should_return_wp_error_object() {
 		$this->assertWPError( is_object_in_term( 12345, 'foo', 'bar' ) );
 	}
+
+	/**
+	 * @ticket 63618
+	 */
+	public function test_term_objects_should_not_be_added_to_cache_when_suspend_cache_addition() {
+		register_taxonomy( 'wptests_tax', 'post' );
+
+		$t = self::factory()->term->create(
+			array(
+				'taxonomy' => 'wptests_tax',
+				'slug'     => 'foo',
+			)
+		);
+
+		$object_id = 12345;
+		wp_cache_delete( $object_id, 'wptests_tax_relationships' );
+
+		$suspend = wp_suspend_cache_addition();
+		wp_suspend_cache_addition( true );
+
+		is_object_in_term( $object_id, 'wptests_tax', $t );
+
+		wp_suspend_cache_addition( $suspend );
+
+		$this->assertFalse( wp_cache_get( $object_id, 'wptests_tax_relationships' ) );
+
+		_unregister_taxonomy( 'wptests_tax', 'post' );
+	}
 }