Fatal error in site_pages API

[zerocrates]

Fatal error: Uncaught Error: Call to a member function getReference() on null in /var/www/localhost/htdocs/omeka-s/application/src/Api/Representation/SiteBlockAttachmentRepresentation.php:34
Stack trace:
#0 [internal function]: Omeka\Api\Representation\SiteBlockAttachmentRepresentation->jsonSerialize()
#1 /var/www/localhost/htdocs/omeka-s/vendor/zendframework/zend-json/src/Json.php(331): json_encode(Array, 15)
#2 /var/www/localhost/htdocs/omeka-s/vendor/zendframework/zend-json/src/Json.php(296): Zend\Json\Json::encodeViaPhpBuiltIn(Array, false)
#3 /var/www/localhost/htdocs/omeka-s/vendor/zendframework/zend-json/src/Json.php(97): Zend\Json\Json::encodeValue(Array, false, Array, false)
#4 /var/www/localhost/htdocs/omeka-s/vendor/zendframework/zend-view/src/Renderer/JsonRenderer.php(151): Zend\Json\Json::encode(Array)
#5 /var/www/localhost/htdocs/omeka-s/application/src/View/Renderer/ApiJsonRenderer.php(43): Zend\View\Renderer\JsonRenderer->render(Array)
#6 /var/www/localhost/htdocs/omeka-s/vendor/zendframework/zend-view/src in /var/www/localhost/htdocs/omeka-s/application/src/Api/Representation/SiteBlockAttachmentRepresentation.php on line 34

I assume this is happening because of an attachment to a private item (this is with an anonymous request).