Node-Webshot uses PhantomJS which in turn uses QtWebkit which doesn't work with AngularJS.
More info: https://github.com/angular/angular.js/issues/2985
Suggestion. Make sure the PhantomJS you have bundled within Node-Webshot is absolutely the latest version. If not, replace the PhantomJS with the latest version and prey for them to have fixed it by now.
If you have access to the command line options of PhantomJS, you could try a few of them in here: https://github.com/ariya/phantomjs/wiki/API-Reference
The ones particularly riging the bell are:
--ignore-ssl-errors=true
--local-to-remote-url-access=true
--web-security=false
