I'm trying to add comment with given date but when I send request via go-jira your api writes comment, but with current date (response code: 201).
Interesting that when I tried to send wrong date, your api returned the parse date error, but when I fix it and send addComment request with my date, jira writes current datetime.
//Request body
... Updated: Created:2017-09-05T17:30:27.443Z ...