Thanks for the files.
(1) I installed the font “for all users” on Windows and then created a new document with a text field, using that font. (Note that it is not enough to put the font in a special Document Fonts folder that only InDesign can read, because Acrobat needs to have access to the font as well, below in Step 5.)
(2) I exported the document to interactive PDF with FormMagic.
(3) It opened in Acrobat, and I ran the FormMagic command at the bottom of the Edit menu in Acrobat.
(4) I saved the PDF after running the FormMagic command and closed Acrobat.
(5)I then uninstalled the font and reopened the PDF. Everything seems in order. The font is nicely embedded, and I can type with it in the text field even though it is not installed on my computer. I’m attaching the PDF.
Are these the exact steps you followed?