facetQuery Rest API throwing 400 error when using nested attributes

Question

I'm getting a 400 when trying to search for a nested attribute facet field

e.g. a post request to the following url will give me

http://xxx-dsn.algolia.net/1/indexes/index_name/facets/work_experience.company/query

{"message":"Cannot search in `work_experience.company` attribute, you need to add `searchable(work_experience.company)` to attributeForFaceting.","status":400}

However a non nested attribute facet search works

http://xxx-dsn.algolia.net/1/indexes/index_name/facets/language_names/query

I've double checked and the facets are correctly added to attributes for faceting.

Any help would be appreciated.

Thanks!