Argument 5 passed to _search_api_batch_indexing_callback() must be of the type array, object given search_api.module:2700

Hey,

I'm getting this error when I try to run drush sapi-i [index name]:

Argument 5 passed to _search_api_batch_indexing_callback() must be of the type array, object given search_api.module:2700

Tried investigating it and I see the $context arg to have been passed with this value:

DrushBatchContext Object                                                                                                        [notice]
(
    [storage:ArrayObject:private] => Array
        (
            [sandbox] => Array
                (
                )

            [results] => Array
                (
                )

            [finished] => 1
            [message] =>
        )

)

Any ideas?