Sales email subject "&" turns to  

[rbncha]

Preconditions

PHP 7.0.1
Mysql 5.6.31
Apache 2.4.23
Magento 2.0.7/2.1.0/2.1.1

Steps to reproduce

1. Admin > Stores > General > General > Store Information > Store Name : change store name something having ampersand "&" like Easy&Piggy
2. Send an order email.

Expected result

1. Order email subjected: Your Easy&Piggy order confirmation

Actual result

1. Your Easy&Piggy order confirmation (& is converted to &)
2. 

[veloraven]

@rbncha thank you for your report.
Could you please add some formatting to the last line? As I see "& is converted to &" instead of "& is converted to &" and it's confusing.
You can just add "" sign before &

[quienti]

Probably same problem, but with mail subject where ' is '
Add '' do not works.
On Magento 2.1.1

[olysenko]

Hi,
internal ticket is created MAGETWO-58663

[calvintwr]

any updates on this issue? i see that this issue has no assignment.

[PieterCappelle]

Quick fix is in di.xml

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Email\Model\Template">
        <plugin name="mail_subject" type="VENDOR\MODULE\Plugin\Template" sortOrder="100" />
    </type>
</config>

In Template.php

namespace VENDOR\MODULE\Plugin;

class Template
{
    public function afterGetSubject(
        \Magento\Email\Model\Template $subject,
        $result
    ) {
        return htmlspecialchars_decode((string)$result, ENT_QUOTES);
    }
}

[magento-engcom-team]

@rbncha, thank you for your report.
We were not able to reproduce this issue by following the steps you provided. If you'd like to update it, please reopen the issue.
We tested the issue on 2.3.0-dev, 2.2.0, 2.1.9

[korostii]

Hi @magento-engcom-team

We tested the issue on 2.3.0-dev, 2.2.0, 2.1.9

That can't be right. As mentioned on the linked PR #9476 , here's the fix: e89d09d
And it seems to be present on 2.2 branch only.