Error with inherited state in htmlbars template

I get the following error with the Ember addon when I try to extend a block with an state:

> TemplateError: Can not apply multiple states at the same time from the exclusive state group ":scope[state|error]"

```
/* block-1.block.css */
:scope[state|error] {
...
}

/* block-2.block.css */
@block-reference block1 from "block-1.block.css";
:scope {
extends: block1
}

/* block-2.hbs */

```
When the state is not inherited, the build is fine:
```
/* block-1.block.css */
:scope[state|error] {
...
}

/* block-1.hbs */

```