Problem with "Back to:"

I have some multipage posts.
The feature “Back to: [here link]” is shown only on last page and leads to the first page (not to previous). I guess it is not very correct.
I remember that in earlier versions of plugin this feature was on all pages (naturally except first) and led to previous page.
Sorry for my bad English; I hope you may understand my explanation.

https://wordpress.org/plugins/sgr-nextpage-titles/