Custom Menu in Widget Area- Sidebar Pages

We have been creating custom menus in the widget area since many of our pages require a menu showing the parent and children but not any grandparents nor parents when you are on that specific parent. I’ve tried looking at different forums (https://wordpress.org/support/topic/sidebar-menu-show-parent-page-and-sister-pages) and external sites for incorporating this specific menu structure into our site but it appears that creating custom menus in the widget area- sidebar pages was the best option.

We have been successful with this but are having a few issues listed below with these custom menus in the widget area- sidebar pages:

1- For some reason, one of our pages is not showing the custom menu although it was configured the same way as the other pages (see screenshot links below).
Please note the default editor also appears to not be working (it either appears blank although there should be content or it has a ‘processing icon’ that keeps spinning.

2- Since this Custom Menu in Widget Area- Sidebar Pages is a parent and children structure (see screenshot “c” below), the background of the menu appears white instead of the same color as the page. I have tried different css codes to fix this but it seems to still contain some white appearing between the links. These are some of the css codes I tried but did not completely fix this:

.widget {
background: #F5F5F5;
}
.widget_nav_menu ul ul li a {
background: #F5F5F5;
}

Any help and clarification would be greatly appreacited.
Thank you!