Hi. There is sourcemap issue in multiple entrypoint with esm

src/
- hello.ts
- index.ts
tsup.config.ts

// src/index.ts
export * from './hello';

// src/hello.ts
export function hello() {
  console.log('hello');
}

// tsup.config.ts
import { defineConfig } from 'tsup';

export default defineConfig({
  entry: ['src/index.ts', 'src/hello.ts'],
  format: ['esm'],
  sourcemap: true,
});

when it build, both index.mjs.map, hello.mjs.map is empty

// dist/hello.mjs.map
{"version":3,"sources":[],"sourcesContent":[],"mappings":"","names":[]}

// dist/index.mjs.map
{"version":3,"sources":[],"sourcesContent":[],"mappings":"","names":[]}

only chunk file (chunk-{hashed}) has sourcemap. maybe chunking has sourcemap issue?

it works correctly with cjs format.

Thanks!