Not working in plain text widget

The plugin works great in normal content. However, I’ve tried adding an email address to a plain text widget in the sidebar and it is not working there. I’ve tried both adding the email address as plain text and adding it as a html mailto link.

The email address is displaying without any protection. I’ve checked the page source as well as with disabling javascript. Email addresses in the page content on the same page are protected however, so the plugin is working. Just not for the text widget. I’ve also tried a WYSIWYG widget, but same result: no protection.

I’m using a plain WordPress install with the TwentySixteen theme and no other plugins active (except when testing with the WYSIWYG widget).