java.lang.ClassCastException: org.elasticsearch.search.aggregations.bucket.terms.ParsedStringTerms cannot be cast to org.elasticsearch.search.aggregations.bucket.terms.StringTerms

I am trying to get aggregations using GROUP By of an attributename and getting the below error.
StringTerms strAggs = response.getAggregations().get(TermsAggregation.AGGREGATION_PREFIX + attributeName);
java.lang.ClassCastException: org.elasticsearch.search.aggregations.bucket.terms.ParsedStringTerms cannot be cast to org.elasticsearch.search.aggregations.bucket.terms.StringTerms
CAn anyone help me understand what this is error is. Did not get much info about ParsedString Terms

Can some one please check and share some pointers