Book: Mastering the American Accent - Lisa Mojsin 2009

How can an American English accent training book mess up such a basic symbol so badly?

This is an IPA vowel all right, just not what the author would have you believe. Take a listen:

#my/video/youtube
U 20250612 YouTube

That does not sound like the vowel in "but" or "fun" at all!

Another example of sloppy typography

From the same book: This is just sloppy and unfortunate typography. The IPA symbols simply should never be displayed in a sans serif font, and the choice of glyph is plain- wrong.