only in patch2:
unchanged:
--- /dev/null
+++ b/redirect.post_update.php
@@ -0,0 +1,15 @@
+<?php
+
+/**
+ * @file
+ * Post update hooks for the Redirect module.
+ */
+
+use Drupal\redirect\RedirectRepository;
+
+/**
+ * Rehash redirects to account for encoded URLs.
+ */
+function redirect_post_update_rehash_redirects_for_encoded_urls(&$sandbox) {
+  RedirectRepository::regenerateRedirectHash($sandbox);
+}
only in patch2:
unchanged:
--- a/src/RedirectRepository.php
+++ b/src/RedirectRepository.php
@@ -2,10 +2,13 @@
 
 namespace Drupal\redirect;
 
+use Drupal\Core\Cache\Cache;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Database\Connection;
+use Drupal\Core\Database\Database;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Language\Language;
+use Drupal\Core\Site\Settings;
 use Drupal\redirect\Entity\Redirect;
 use Drupal\redirect\Exception\RedirectLoopException;
 
@@ -181,4 +184,73 @@ class RedirectRepository {
   public function loadMultiple(array $redirect_ids = NULL) {
     return $this->manager->getStorage('redirect')->loadMultiple($redirect_ids);
   }
+
+  /**
+   * Regenerate the redirect hash as part of a Drupal update.
+   *
+   * @param array $sandbox
+   *   Stores information for batch updates.
+   *
+   * @see hook_post_update_NAME()
+   */
+  public static function regenerateRedirectHash(array &$sandbox) {
+    if (!isset($sandbox['progress'])) {
+      $sandbox['progress'] = 0;
+      $sandbox['updated'] = 0;
+      $sandbox['current_rid'] = 0;
+      // Note, because MySQL can treat `foo = LOWER(foo)`, all records must be
+      // checked.
+      $sandbox['max'] = Database::getConnection()
+        ->query('SELECT COUNT(1) FROM {redirect}')
+        ->fetchField();
+    }
+    $batch_size = Settings::get('entity_update_batch_size', 50);
+
+    $result = \Drupal::database()->select('redirect', 'r')
+      ->fields('r', [
+        'rid', 'redirect_source__path', 'redirect_source__query', 'language', 'hash',
+      ])
+      ->condition('rid', $sandbox['current_rid'], '>')
+      ->range(0, $batch_size)
+      ->orderBy('rid')
+      ->execute();
+
+    foreach ($result as $row) {
+      $query = !empty($row->redirect_source__query) ? unserialize($row->redirect_source__query) : [];
+      $new_hash = Redirect::generateHash($row->redirect_source__path, (array) $query, $row->language);
+      if ($row->hash !== $new_hash) {
+        // Do a direct query to speed things up.
+        $query = \Drupal::database();
+        $query->update('redirect')
+          ->fields(['hash' => $new_hash])
+          ->condition('rid', $row->rid)
+          ->execute();
+        $sandbox['updated']++;
+      }
+      $sandbox['progress']++;
+      $sandbox['current_rid'] = $row->rid;
+    }
+    // Reset caches.
+    $sandbox['#finished'] = empty($sandbox['max']) ? 1 : ($sandbox['progress'] / $sandbox['max']);
+
+    if ($sandbox['#finished'] >= 1) {
+      if ($sandbox['updated']) {
+        // Invalidate 'redirect_list' cache tag when a redirect hash was
+        // updated.
+        Cache::invalidateTags(['redirect_list']);
+      }
+
+      $message = \Drupal::translation()->formatPlural(
+        $sandbox['updated'],
+        '@count redirect was updated.',
+        '@count redirects were updated.',
+        ['@count' => $sandbox['updated']]
+      );
+      \Drupal::messenger()->addStatus($message);
+
+      return $message;
+    }
+    return NULL;
+  }
+
 }