Export from Jira Service Desk customer view throws error

Description
When exporting an empty multi-line text custom field created on the Request Form of Jira Service Desk with the Wiki markup on the mapping from the Customer View, Xporter will throw an error and it will not be possible to export the Template.

How to reproduce

1. Create a multi-line text custom field to the Request Form on a Jira Service Desk project
2. Create a Request on Jira Service Desk and leave the created custom field empty (without value)
3. Create a template to export the created custom field with the Wiki markup
4. Export the template on the Customer view page

Actual result/Attachments
Xporter throws an error generating the template

Expected result
It should generate the template.