git-format-patch does not encode lines starting with "From"

Summary =======

git-format-patch in 2.32.0 fails to quote/escape lines starting with "From ", and mbox readers conclude there is an empty mail.

Observed ========

$ git commit -m 'subject

From ffffffffffffffffffffffffffffffffffffffff Mon Sep 17 00:00:00 2001
with love.'
$ git format-patch HEAD^!
$ head 0001-subject.patch
From d489071b4855a49b32e9b5ae5addd982d2ed8d7d Mon Sep 17 00:00:00 2001
From: Jan Engelhardt <jengelh@inai.de>
Date: Sun, 27 Jun 2021 20:04:20 +0200
Subject: [PATCH] subject

From ffffffffffffffffffffffffffffffffffffffff Mon Sep 17 00:00:00 2001 with love.

$ git reset --hard HEAD^ $ git am -p0 0001-subject.patch Patch is empty. When you have resolved this problem, run "git am --continue".

Expected to see ===============

$ head 0001-subject.patch
From d489071b4855a49b32e9b5ae5addd982d2ed8d7d Mon Sep 17 00:00:00 2001
From: Jan Engelhardt <jengelh@inai.de>
Date: Sun, 27 Jun 2021 20:04:20 +0200
Subject: [PATCH] subject

with love.