FORWARD AS ATTACHMENT not creating attachments

I wish to forward emails as attached text files to the newly created email. In other words, the text of the email to be forwarded is put into a text file and listed in the Attachments drop-down menu in the email's window. In the Sent Messages folder I should see the name of the file and a Quick Look and Save button.

FORWARD AS ATTACHMENT does not seem to create such emails with attached files. What I'm seeing is the email-to-be-forwarded in the text section of the email, with a black frame and a yellow background, with concise header information at the top and the email contents belo on a blue background. It doesn't seem like an attached file to me.

USE CASE:

I want to forward longer emails (mailing list emails and online magazines) to my Send to Kindle email address at Amazon so they can send the file in ebook format to my Kindle via WIFI. This works fine if I manually copy email text into a text file, save it, and then drag it into a new email.