rollup-plugin-string don't work

case:

I'm in migration process from rollup only build pipeline to broccoli pipeline.
I need to keep templates in independent files and import it as variable from js.

trying to setup pipeline using https://github.com/TrySound/rollup-plugin-string and broccoli-rollup - but, it's not working at all (

Priginal rollup pipeline works with this plugin without isssues.