The code in the wp_footer hook seems to be at the root cause. I’m still having issues with where it lands, but, at least” it’s going back to the right page. (FWIW this is the code you pointed me to for resolving the menu getting “stuck” down on mobile. I haven’t worked on mobile here, so not sure if that is still an issue.)
Hoping this is still on topic – if I change the hover color to red, only the “Blog” item changes when I go over it. After using on of the other items, it changes after the scroll. Plugin issue?