Is there something wrong with Being Invisible on Amazon?

Big Question - I just received a PM from someone who purchased Being Invisible and they report that the book acted 'wonky' ( a technical term). The person said that the font changed from their preset 11 point to 7 without warning.

If you have purchased the book, or are reading it on your Kindle, please help me out and look.

Let me know if the problem is on my end.

Thank you kind people,

Leslie