Issue #3493035 attach the correct terms to posts.

Closes #3493035

src/Plugin/migrate/source/Posts.php

@@ -130,12 +130,19 @@ class Posts extends SqlBase {
    */
   protected function getTaxonomyTerms(Row $row, string $taxonomy) {
     $query = $this->select('term_relationships', 'tr')
-      ->fields('tr', ['term_taxonomy_id']);
-
-    $query->join('term_taxonomy', 'tt', 'tr.term_taxonomy_id = tt.term_taxonomy_id and tt.taxonomy = :tag_taxonomy', [
-      ':tag_taxonomy' => $taxonomy,
-    ]);
-    $query->condition('object_id', $row->get('id'));
+      ->fields('t', ['term_id', 'name']);
+    $query->join(
+      'term_taxonomy',
+      'tt',
+      'tr.term_taxonomy_id = tt.term_taxonomy_id'
+    );
+    $query->join(
+      'terms',
+      't',
+      'tt.term_id = t.term_id'
+    );
+    $query->condition('tt.taxonomy', $taxonomy)
+      ->condition('tr.object_id', $row->get('id'));
 
     return array_values($query->execute()->fetchAllKeyed(0, 0));
   }