Fehlerhaftes MIME Encoding der Headers "From" und "X-Original-From"

Ausgangslage

ERPNext E-Mail-Account:

Name ÄäÖöÜü
Adresse info@msmr.ch

Mailversand durch folgenden Code:
frappe.sendmail(sender="MV Zürich <info@msmr.ch>", recipients=['joel@msmr.ch'], message="xxx", subject="test", reply_to="info@msmr.ch")

Erwartetes- vs. Effektives-Verhalten

Case 1
E-Mail-Account Settings:

Always use Account's Email Address as Sender
Always use Account's Name as Sender's Name

Erwartete Header:

From: =?utf-8?q?MV_Z=C3=BCrich?= <info@msmr.ch>

Tatsächlicher Header:

From: =?utf-8?b?TVYgWsO8cmljaCA8aW5mb0Btc21yLmNoPg==?= --> ❌

Testresultat: ❌ Failed

Case 2
E-Mail-Account Settings:

Always use Account's Email Address as Sender
Always use Account's Name as Sender's Name

Erwartete Header:

From: =?utf-8?q?MV_Z=C3=BCrich?= <info@msmr.ch>
X-Original-From: =?utf-8?q?MV_Z=C3=BCrich?= <info@msmr.ch>

Tatsächlicher Header:

From: =?utf-8?q?MV_Z=C3=BCrich?= <info@msmr.ch> --> ✅
X-Original-From: =?utf-8?b?TVYgWsO8cmljaCA8aW5mb0Btc21yLmNoPg==?= --> ❌

Testresultat: ❌ Failed

Case 3
E-Mail-Account Settings:

Always use Account's Email Address as Sender
Always use Account's Name as Sender's Name

Erwartete Header:

From: =?utf-8?q?=C3=84=C3=A4=C3=96=C3=B6=C3=9C=C3=BC?= <info@msmr.ch>
X-Original-From: =?utf-8?q?MV_Z=C3=BCrich?= <info@msmr.ch>

Tatsächlicher Header:

From: =?utf-8?q?=C3=84=C3=A4=C3=96=C3=B6=C3=9C=C3=BC?= <info@msmr.ch> --> ✅
X-Original-From: =?utf-8?q?MV_Z=C3=BCrich?= <info@msmr.ch> --> ✅

Testresultat: ✅ Passed

Case 4
E-Mail-Account Settings:

Always use Account's Email Address as Sender
Always use Account's Name as Sender's Name

Erwartete Header:

From: =?utf-8?q?=C3=84=C3=A4=C3=96=C3=B6=C3=9C=C3=BC?= <info@msmr.ch>
X-Original-From: =?utf-8?q?MV_Z=C3=BCrich?= <info@msmr.ch>

Tatsächlicher Header:

From: =?utf-8?q?=C3=84=C3=A4=C3=96=C3=B6=C3=9C=C3=BC?= <info@msmr.ch> --> ✅
X-Original-From: =?utf-8?b?TVYgWsO8cmljaCA8aW5mb0Btc21yLmNoPg==?= --> ❌

Testresultat: ❌ Failed