GET /api/v1/tickets return err500 when sending fields parameter

GET /api/v1/tickets return err500 when sending fields parameter

When i call GET /api/v1/tickets  and fill in the "fields" parameter, i get response code 500. When i remove the parameter, everything is fine.

not working: GET /api/v1/tickets?from=1&limit=100&fields=contactId%2Cstatus&include=assignee
working: GET /api/v1/tickets?from=1&limit=100&include=assignee