Reproduction link or steps

https://stackblitz.com/edit/github-mab9td2g?file=package.json

What is expected?

With tsdown --unbundle -f cjs -f esm, to have the build working.

What is actually happening?

thread 'tokio-runtime-worker' panicked at crates/rolldown/src/utils/chunk/render_chunk_exports.rs:157:67:
no entry found for key
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
worker (tid = 43) sent an error! unreachable
[Error [RuntimeError]: unreachable]

Any additional comments?

Seems that the problem comes from the export from external deps located in subdirectories with the unbundle and cjs format options.