diff -u b/core/modules/field/lib/Drupal/field/Plugin/Core/Entity/FieldInstance.php b/core/modules/field/lib/Drupal/field/Plugin/Core/Entity/FieldInstance.php
--- b/core/modules/field/lib/Drupal/field/Plugin/Core/Entity/FieldInstance.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/Core/Entity/FieldInstance.php
@@ -400,7 +400,7 @@
     if ($this->bundle != $original->bundle && empty($this->bundle_rename_allowed)) {
       throw new FieldException("Cannot change an existing instance's bundle.");
     }
-    if ($this->field_name != $original->field_name || $this->field_uuid != $original->field_uuid) {
+    if ($this->field_uuid != $original->field_uuid) {
       throw new FieldException("Cannot change an existing instance's field.");
     }