I've just tested locally with your payload and it's not triggering the same stack trace too. The stack trace is also clearly showing that it's trying to parse comment events:
``` at com.ceilfors.jenkins.plugins.jiratrigger.webhook.WebhookCommentEventJsonParser.parse(WebhookCommentEventJsonParser.groovy:40) ```
Additionally, the URL of your JIRA doesn't seem to be JIRA Cloud. Atlassian hasn't deprecated the name field in JIRA Server.
The issue-updated-event.json may contain comments, especially when you've left a comment in JIRA. JIRA will actually trigger issue-updated-event on comments too (I can't remember which version).
Is it worth double checking if that's the only event you get? If it makes it easier, you can enable the FINE logging level to get all the webhook events printed out, by following this guide: https://github.com/jenkinsci/jira-trigger-plugin#troubleshooting