How to stop Mac Mail from adding mailto: whenever I type an email address

In previous versions of MacOS, when you typed an email address in the body of a message, Mail would insert a <mailto:user@host.domain.com> after the email address. It was super annoying.

I found that I could disable this behavior by unchecking the Composing setting "Add Link Previews".

I have just installed MacOS Sequoia and even though I have that setting disabled and even though I have the message style set to Plain text, Mail inserts a mailto: version after the email address. Even worse, you can't tell it has done this until after the message is sent.

How I can I stop Mail from modifying my plain text message by inserting mailto: links for email addresses?