I need to be able to copy the values from 3 existing multi-line open text custom fields from one project issue record into the description field of the new issue record when the record is "moved" from it's parent project into a new one. This is because the destination project does not contain the same custom fields, and we don't need them there. I've read through the advanced documentation on how to do this, but still not getting the value to carry over. Any help to get this working correctly would be greatly appreciated. Thanks!
{
"fields": {
"description": {{issue.parent.customfield_10158}}
{{issue.parent.customfield_10157}}
{{issue.parent.customfield_10054}}
}
} 
Error I get from the Audit Log:
