Unfortunatly the issue persists. All permissions are inherited: True. This happens when the dashboard is in a shared folder and the permissions come from the parent folder, not from the dashboard itself.

permissions: {'object_id': '/dashboards/<redacted>', 'object_type': 'dashboard', 'access_control_list': [{'user_name': '<redacted>', 'display_name': '<redacted>', 'all_permissions': [{'permission_level': 'CAN_EDIT', 'inherited': True, 'inherited_from_object': ['/directories/<redacted>']}]}, {'user_name': '<redacted>', 'display_name': '<redacted>', 'all_permissions': [{'permission_level': 'CAN_MANAGE', 'inherited': True, 'inherited_from_object': ['/directories/<redacted>']}]}, {'group_name': '<redacted>', 'all_permissions': [{'permission_level': 'CAN_MANAGE', 'inherited': True, 'inherited_from_object': ['/directories/']}]}]}