I also see this in the logs:
2018-05-01T10:19:14.683Z - info: Rendering template {shortid:ryf6T9r6z, recipe:phantom-pdf, engine:handlebars, preview:true} requestId=29
(node:10) Warning: a promise was created in a handler at usr/src/app/node_modules/jsreport-authentication/lib/authentication.js:446:7 but was not returned from it, see http://goo.gl/rRqMUw
at Function.Promise.cast (/usr/src/app/node_modules/bluebird/js/release/promise.js:196:13)