Error while doing sort on field for searchConnection method

Error while doing sort on field for searchConnection method. Specially its not working with "date" type of fields.

Query
postConnection(query: {bool: {must: [
{term: {type: {value: "type"}}}]}},
sort: [post_date__desc], first: 12, after: $after) {

Output
 {"errors":[{"message":"Cannot read property 'join' of undefined","locations":[{"line":2,"column":3}],"path":["postConnection"]}],"data":{"postConnection":null}}

Please let me know if I am missing something.

Start by reproducing the reported postConnection query with the post_date__desc sort and inspect the searchConnection sorting path, especially handling for date fields. Done means the query returns sorted results without the Cannot read property 'join' of undefined error; no file or test location is identified in the issue.

Written by the indexing model from the issue text.