magento2: Configuration -> Advanced -> System ERROR

Preconditions (*)

1. Magento 2.2-develop

Steps to reproduce (*)

1. Install magento
2. Go to admin -> stores -> configurations -> advanced -> system
3. Reload page WITHOUT SAVING configurations.

Expected result (*)

1. Page reloads without errors and with content

Actual result (*)

1. Page content empty because of errors, that appears in developer mode: 4 exception(s): Exception #0 (Magento\Framework\Exception\AlreadyExistsException): Unique constraint violation found Exception #1 (Magento\Framework\DB\Adapter\DuplicateException): SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry ‘default-0-system/full_page_cache/varnish/access_list’ for key ‘DEV_CORE_CONFIG_DATA_SCOPE_SCOPE_ID_PATH’, query was: INSERT INTO dev_core_config_data (path, value) VALUES (?, ?) Exception #2 (Zend_Db_Statement_Exception): SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry ‘default-0-system/full_page_cache/varnish/access_list’ for key ‘DEV_CORE_CONFIG_DATA_SCOPE_SCOPE_ID_PATH’, query was: INSERT INTO dev_core_config_data (path, value) VALUES (?, ?) Exception #3 (PDOException): SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry ‘default-0-system/full_page_cache/varnish/access_list’ for key ‘DEV_CORE_CONFIG_DATA_SCOPE_SCOPE_ID_PATH’

Related issue #13224