Hi,
I have experimented a bit with that option in fact and I get different results, generally either the email getting sent and the download page not working or vice versa, as it is at the moment.
Right now that option is set at Pending Payment since I have found that it has the best results.
Regards,
Mark
Adding to the previous post:
Using WordPress 4.8.2 with StoreFront theme.
WooCommerce 3.2.0, Ebook Store 5.575, PostmanSMTP 1.7.2