As per as https://www.drupal.org/coding-standards/docs#file (Last paragraph)....

As per as https://www.drupal.org/coding-standards/docs#file (Last paragraph).

files that contain a namespaced class/interface/trait, whose file name is the class name with a .php extension, and whose file path is closely related to the namespace (under PSR-4 or a similar standard), SHOULD NOT have a @file documentation block.

Tested this on 8.x branch and working fine.