When updating the uniqueValueInfos property in the renderer, the following error message is returned, "Error: "Uncaught TypeError: Cannot read property 'data' of null."
This issue is no longer reproducible in the latest version of ArcGIS API for JavaScript. Test the functionality by through the following CDN link, https://github.com/Esri/feedback-js-api-next.
Reach out to Esri Technical Support if the issue still persists.