Why do people sign up for a reader magnet and not download it?

I have a reader magnet, a three-chapter book I offer on BookFunnel through group promotions. Over and over, people put in their email addresses and thus sign up for my email list without actually downloading the book (this shows when I extract the new readers from bookfunnel). Do you know why this happens?

I’m glad to have people on my list (assuming they want to be there), but I’d even more like them to read my reader magnet. I do have a welcome sequence that reminds them of the link to download the book, so some of these may go back and download it after all, but my download stats on that page don’t seem high, so I don’t think so.

I would think people wouldn’t want to give away their email addresses for nothing, so I’m worried this is people struggling with the technical process of the download. Does anyone else experience this?