Hi,
When I add attachment in the new issue view, it doesn't return by REST API. Old view worked correctly.

/rest/api/2/issue/ROADMAP-13527?fields=attachment
{"expand":"renderedFields,names,schema,operations,editmeta,changelog,versionedRepresentations","id":"20387","self":"https://bvgoswami.atlassian.net/rest/api/2/issue/20387","key":"ROADMAP-13527"}