diff -u b/core/modules/taxonomy/src/Plugin/views/argument_validator/TermName.php b/core/modules/taxonomy/src/Plugin/views/argument_validator/TermName.php
--- b/core/modules/taxonomy/src/Plugin/views/argument_validator/TermName.php
+++ b/core/modules/taxonomy/src/Plugin/views/argument_validator/TermName.php
@@ -81,6 +81,8 @@
     // $terms are already bundle tested but we need to test access control.
     foreach ($terms as $term) {
       if ($this->validateEntity($term)) {
+        // Always use the term ID as argument.
+        $this->argument->argument = $term->id();
         // We only need one of the terms to be valid, so return TRUE when we
         // find one.
         return TRUE;