[Vuejs]-Why router.base doesn't work for static src during 'npm run build' (Nuxt js)?

Have you made sure that the environment variable ENTITY is set in the environment you run the build in?

To make sure it’s not a problem with the env var you could try temporarily changing it to

const ROUTER_BASE = "/my/";

If it works with that base hard coded then it must be a problem with the enviroment variable you’re using.