diff --git a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
index b11807b430..ecfa56409a 100644
--- a/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
+++ b/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php
@@ -1368,6 +1368,17 @@ protected function createSharedTableSchema(FieldStorageDefinitionInterface $stor
               $new_keys = [];
               if (!empty($schema[$table_name]['primary key']) && in_array($name, $schema[$table_name]['primary key'], TRUE)) {
                 $new_keys = ['primary key' => $schema[$table_name]['primary key']];
+
+                // If the field is part of a primary key, it might be a serial
+                // field. Serial fields are incorrectly stored as integer fields
+                // in the field schema, so we adapt the schema here manually.
+                // @todo Remove this in
+                //  https://www.drupal.org/project/drupal/issues/2928906
+                $base_table_serial = ($created_field_name === $this->entityType->getKey('id')) && ($table_name === $this->storage->getBaseTable());
+                $revision_table_serial = ($created_field_name === $this->entityType->getKey('revision')) && ($table_name === $this->storage->getRevisionTable());
+                if (($specifier['type'] === 'int') && ($base_table_serial || $revision_table_serial)) {
+                  $specifier['type'] = 'serial';
+                }
               }
 
               // Check if the field exists because it might already have been
@@ -2432,11 +2443,13 @@ private function dropPrimaryKey(FieldStorageDefinitionInterface $storage_definit
       // schema, so we explicitly check the conditions for marking it serial.
       // @todo Remove this in
       //  https://www.drupal.org/project/drupal/issues/2928906
-      $base_table_serial = ($field_name === $this->entityType->getKey('id')) && ($table_name === $this->entityType->getBaseTable());
-      $revision_table_serial = ($field_name === $this->entityType->getKey('revision')) && ($table_name === $this->entityType->getRevisionTable());
+      $base_table_serial = ($field_name === $this->entityType->getKey('id')) && ($table_name === $this->storage->getBaseTable());
+      $revision_table_serial = ($field_name === $this->entityType->getKey('revision')) && ($table_name === $this->storage->getRevisionTable());
       if ($base_table_serial || $revision_table_serial) {
         foreach ($schema['primary key'] as $column_name) {
-          $schema_handler->changeField($table_name, $column_name, $column_name, $schema['fields'][$column_name]);
+          if ($schema['fields'][$column_name]['type'] === 'int') {
+            $schema_handler->changeField($table_name, $column_name, $column_name, $schema['fields'][$column_name]);
+          }
         }
       }
       $schema_handler->dropPrimaryKey($table_name);
diff --git a/core/modules/system/tests/src/Functional/Entity/Update/SqlContentEntityStorageSchemaConverterTest.php b/core/modules/system/tests/src/Functional/Entity/Update/SqlContentEntityStorageSchemaConverterTest.php
index 4b7fccbeb5..639be89565 100644
--- a/core/modules/system/tests/src/Functional/Entity/Update/SqlContentEntityStorageSchemaConverterTest.php
+++ b/core/modules/system/tests/src/Functional/Entity/Update/SqlContentEntityStorageSchemaConverterTest.php
@@ -220,15 +220,9 @@ public function testMakeRevisionableErrorHandling() {
     foreach ($new_storage_definitions as $storage_definition) {
       $new_field_schema_data[$storage_definition->getName()] = $this->installedStorageSchema->get('entity_test_update.field_schema_data.' . $storage_definition->getName(), []);
     }
-    // Before https://www.drupal.org/project/drupal/issues/2928906 the field
-    // schema data of integer identifier fields was incorrectly stored as 'int'
-    // instead of 'serial'. So we explicitly make that change before checking
-    // equality.
-    /* @see \Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema::hasColumnChanges() */
-    $this->assertSame($original_field_schema_data['id']['entity_test_update']['fields']['id']['type'], 'int');
-    $original_field_schema_data['id']['entity_test_update']['fields']['id']['type'] = 'serial';
-    // Also add keys that are stored in the field schema as of
-    // https://www.drupal.org/project/drupal/issues/2928906.
+    // Before https://www.drupal.org/project/drupal/issues/2929120 various keys
+    // were missing from the field schema, so we explicitly add those before
+    // checking equality.
     $this->assertFalse(isset($original_field_schema_data['id']['entity_test_update']['primary key']));
     $original_field_schema_data['id']['entity_test_update']['primary key'] = ['id'];
     $this->assertFalse(isset($original_field_schema_data['id']['entity_test_update_data']['primary key']));