Batched Notification emails have an empty content when triggered by a custom event using the Issue created template

Summary

Batched Notification emails have an empty content when triggered by a custom event using the Issue created template.

Steps to Reproduce

• Go to ⚙ > System > Batching email notifications and enable batched notifications
• Go to ⚙ > System > Events
  • Create a custom event using the Issue Created event as a template
    
• Edit any workflow as follows:
  • Click on the transition triggered when an issue is created
  • Click on the Post functions link from this transition
  • Change the event fired in the post functions to the custom event
    
  • Publish the new workflow
• Open a new ticket using this workflow
• Wait for the batched notifications to be received
• Check the content of the batched notification email

Expected Results

The batched notification contains:

• an sentence saying "This issue has been CREATED"
• the details about this tickets fields (Summary, Issue Type, Priority, etc...)
  

Actual Results

The batched notification is almost empty. It contains the issue key and summary and a link to it, but it's missing the rest of the information:

Workaround

• Fire the default Issue Created event during the Create transition
• Or disable the batched notifications feature