Bug 5.7.1 Recipient not found processed as Soft Bounce

There is a bug in this version
A

Alpha1

Guest
This clearly should be a hard bounce:

Code:

Code:
Action: failed
Final-Recipient: rfc822; xxx@tutanota.com
Diagnostic-Code: smtp; 550 5.7.1 <xxx@tutanota.com>: Recipient address rejected: Recipient not found
Status: 5.7.1

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