HTML encoding in body of email

I'm new to grav and I'm trying to build a simple email form using the form and email plugins.
I managed to send emails all right, but I get some HTML-encoded characters in the body of my messages.
This seems to only happen for single and double quotes. Accents and new lines work fine.

I tried with both of these settings in my form page's process :
body: "{% include 'forms/default/data.txt.twig' %}"
content_type: 'text/plain'

and
body: "{% include 'forms/default/data.html.twig' %}"
content_type: 'text/html'

And idea how I could fix that ?

Seems like it's working with the plain text setting, don't know why it wasn't when I first posted this.