I'm trying to create FetureLayer using client-side graphics. here is my code;
when i change the version from 4.18 to 4.20, it works this codepen code.
But i'm using arcgis/core npm package (version 4.20) in my own project. 4.18 npm package is working well but when i change the version to 4.20, i couldn't add feature layer on map.
Can you provide a git repo of your issue. I copied your codepen into a simple app and the layer works ok.
Not sure what the issue you are seeing is.