I created a new CiviVolunteer project and have several successful sign-ups, but one volunteer reported getting this error:
"API permission check failed for VolunteerUtil/getbeneficiaries call; insufficient permission: require edit own volunteer projects"
The successful sign-ups are a mix of named users and anonymous users. The failed sign-up is an anonymous user. This person has successfully signed up for previous projects. I have not changed permission settings recently and have not experienced this error on earlier projects.
I didn't have any issues creating or editing it as admin, but I noticed I get this same error as admin on both the Wordpress and Drupal sandboxes by simply selecting "Manage Volunteer Projects":