Duplication of folder referent for next_posts_link, previous_posts_link

Note: I’ve had to deal with a Trojan horse infection with this WordPress site before and have changed the permalink structure at least once. That might be part of my issue here.

For some time now, on my WP https://www.spiritualmanna.info, when one does a search or simply wants to look at previous or next entries, there is a doubling up of the folder structure (it should be /faith/manna/?…, but it comes up as /faith/manna/faith/manna/?…). If one manually removes the duplication, the function works.

I’m assuming that the difficulty is some kind of duplication or something in the definition of next_posts_link and previous_posts_link , but I have no idea where to find such definitions and what change would need to be made.

I have upgraded WP many times and the problem remains.

Help?

ELDV