If it is intended that relation endpoints (from relation dummy field widget display) should be shown to certain role, view relations permission should be given to those roles.
The security problem with access to results of any view display was corrected in this release.
The vulnerability allowed to modify request and receive results of any view display if it was accessible for the current user.
This release provides a mechanism that allows you to secure view displays that are arbitrarily available via the Views resource. You will now be able to whitelist/blacklist specific view displays from being displayed.