When using DFS clustering and Postgres SQL adding Image will fail with exception:

Doctrine\DBAL\Exception\
SyntaxErrorException

An exception occurred while executing 'INSERT INTO ezdfsfile (name, name_hash, name_trunk, mtime, size, scope, datatype) VALUES (:name, :name_hash, :name_trunk, :mtime, :size, :scope, :datatype) ON DUPLICATE KEY UPDATE datatype=VALUES(datatype), scope=VALUES(scope), size=VALUES(size), mtime=VALUES(mtime)' with params ["var\/site\/storage\/images\/1\/6\/2\/0\/261-1-eng-GB\/31.png", "f85fc08adcb068d13ba0f9bef882f675", "var\/site\/storage\/images\/1\/6\/2\/0\/261-1-eng-GB\/31.png", 1566392625, 439644, "image", "image\/png"]: SQLSTATE[42601]: Syntax error: 7 ERROR: syntax error at or near "DUPLICATE" LINE 4: ON DUPLICATE KEY UPDATE ^

Steps to reproduce
1. Clean installation of eZ Platform 2.5.3 with PostgresSQL
2. Set up DFS clustering
3. Go to the Back Office, create a new Image Content. Publish it.