Issue Summary

The customer uses a Jira Automation rule with a Send email action to send JSON-formatted text in the email body to an external system.

Previously, the outgoing email’s Content-Type header was text/plain, and Power Automate successfully treated the body as plain text and processed the JSON.

Since around December 15, the same Automation email is now sent with Content-Type: multipart/alternative. External systems detect the body as HTML instead of plain text, causing downstream processing to fail.

Based on EML samples before and after the issue started, the only significant difference is the change in Content-Type from text/plain to multipart/alternative for outgoing Automation emails.

Steps to Reproduce

1. In Jira Cloud, create an Automation rule, e.g.:

• • Trigger: Issue created (or any trigger)

• • Action: Send email

1. Configure the Send email action:

• • To: any inbox where you can download the raw EML

• • Subject: any text 

• • Content: paste some JSON as plain text, for example:
     {{}}

    {  
    "issueKey": "{{issue.key}}",  
    "summary": "{{issue.summary}}",  
    "status": "{{issue.status.name}}" 
    }

    {{}}

1. Save and enable the rule.

1. Trigger the rule by creating an issue.

1. In the mailbox, retrieve the received email and inspect the raw EML.

1. Check the headers and MIME structure.

Expected Results

• The outgoing Automation email is sent with:

• • Content-Type: text/plain (or at least a plain-text part that external processors can reliably treat as text).

• External systems detect and process the email body as plain text, allowing JSON parsing to succeed (as it did before ~Dec 15).

Actual Results

• The outgoing Automation email is now sent with:

• • Content-Type: multipart/alternative

• External systems detect the body as HTML, not as plain text.

• As a result, existing flows that expect a plain-text JSON payload fail (e.g. JSON parse or string manipulation actions error out).

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available