Reading Settings for "Posts Page" Linking to Index Instead..?

I have a static page as my homepage. I am trying to add a link to the actual “blog” part of my website to the navigation.

I have changed the “reading settings” to make the “posts page” link to a page called “blog”. However, it keeps linking back to the homepage instead!

I have tried changing the “page attributes” for the Blog page from Default Template to Page, but that didn’t work.

I know the settings are being saved correctly and working because I chose a different page for my static homepage (about) and it worked fine. It must be something with the theme, but I have no idea where to start….

https://www.rleighphotography.com

Thank you!