diff --git a/core/modules/migrate/src/Plugin/migrate/id_map/Sql.php b/core/modules/migrate/src/Plugin/migrate/id_map/Sql.php
index c542293..14a0a7a 100644
--- a/core/modules/migrate/src/Plugin/migrate/id_map/Sql.php
+++ b/core/modules/migrate/src/Plugin/migrate/id_map/Sql.php
@@ -183,7 +183,20 @@ public static function create(ContainerInterface $container, array $configuratio
    *   An hash containing the hashed values of the source identifiers.
    */
   public function getSourceIDsHash(array $source_id_values) {
-    return hash('sha256', serialize(array_map('strval', array_values($source_id_values))));
+    // When looking up the destination ID we require an array with both the
+    // source key and value, e.g. ['nid' => 41]. In this case, $source_id_values
+    // need to be ordered the same order as $this->sourceIdFields().
+    // However, the Migration process plugin doesn't currently have a way to get
+    // the source key so we presume the values have been passed through in the
+    // correct order.
+    if (!isset($source_id_values[0])) {
+      $source_id_values_keyed = [];
+      foreach ($this->sourceIdFields() as $field_name => $source_id) {
+        $source_id_values_keyed[] = $source_id_values[$field_name];
+      }
+      $source_id_values = $source_id_values_keyed;
+    }
+    return hash('sha256', serialize(array_map('strval', $source_id_values)));
   }
 
   /**
diff --git a/core/modules/migrate/tests/src/Unit/RowTest.php b/core/modules/migrate/tests/src/Unit/RowTest.php
index f0f5dad..b723fa5 100644
--- a/core/modules/migrate/tests/src/Unit/RowTest.php
+++ b/core/modules/migrate/tests/src/Unit/RowTest.php
@@ -201,30 +201,30 @@ public function testSourceIdValues() {
    */
   public function testMultipleSourceIdValues() {
     // Set values in same order as ids.
-    $multi_source_ids = $this->testSourceIds + array(
-      'vid' => 'Node revision',
-      'type' => 'Node type',
-      'langcode' => 'Node language',
-    );
-    $multi_source_ids_values = $this->testValues + array(
-      'vid' => 1,
-      'type' => 'page',
-      'langcode' => 'en',
-    );
+    $multi_source_ids = $this->testSourceIds + [
+        'vid' => 'Node revision',
+        'type' => 'Node type',
+        'langcode' => 'Node language',
+      ];
+    $multi_source_ids_values = $this->testValues + [
+        'vid' => 1,
+        'type' => 'page',
+        'langcode' => 'en',
+      ];
     $row = new Row($multi_source_ids_values, $multi_source_ids);
     $this->assertSame(array_keys($multi_source_ids), array_keys($row->getSourceIdValues()));
 
     // Set values in different order.
-    $multi_source_ids = $this->testSourceIds + array(
+    $multi_source_ids = $this->testSourceIds + [
         'vid' => 'Node revision',
         'type' => 'Node type',
         'langcode' => 'Node language',
-      );
-    $multi_source_ids_values = $this->testValues + array(
+      ];
+    $multi_source_ids_values = $this->testValues + [
         'langcode' => 'en',
         'type' => 'page',
         'vid' => 1,
-      );
+      ];
     $row = new Row($multi_source_ids_values, $multi_source_ids);
     $this->assertSame(array_keys($multi_source_ids), array_keys($row->getSourceIdValues()));
   }