Hard bounces reporting as soft

[violens]

I seem to be getting most of my hard bounces reporting as soft.
Here is a header example that reported soft. Are there any adjustments available for better accuracy?

This is a MIME-formatted message.
Portions of this message may be unreadable without a MIME-capable mail program.

This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.

[email protected]

Reporting-MTA: dns;smtp-e****.r*******.com
Received-From-MTA: dns;r********
Arrival-Date: Thu, 25 Jan 2007 18:48:37 -0500

Final-Recipient: rfc822;[email protected]
Action: failed
Status: 5.5.0
Diagnostic-Code: smtp;554 delivery error: dd This user doesn't have a yahoo.com account ([email protected]) [0] - mta330.mail.mud.yahoo.com

E Bounce Report
Soft [email protected] Undefined protocol status 1/25/2007 1

 

[stanbusk]

This is likely because 5.5.4 is defined as a soft bounce. Please open a support ticket with the bounce raw source so we can check this.