Upon initial setup of new registration page, the page access modal & page both fail with empty default checkbox value.
1. Create new custom registration page for any given user role.
2. After creation, you'll be presented with the Multiple Registration pages access settings link in both the messages & below the list of created pages.
3. When clicking on this link, ajax will fail or the page will fail with Warning: foreach() argument must be of type array|object, null given, this is because the multiple_registration_pages_allowed_list is empty by default.
Setting default value within AccessSettingsPageForm.php to something general such as administrator.
'#default_value' => $config->get('multiple_registration_pages_allowed_list') ?: ['administrator' => 'administrator'],
Active
3.2
Code
Using patches, whether merge requests as a patch ensuring the patch is from a trusted source, accurately addresses the issue without introducing new vulnerabilities, and is applied correctly. So the patch file has been provided.