Pages, contact forms, testimonials, etc are all "posts now."

I have a problem where two out of four of our websites on the same domain have an issue where a lot of the created content, regardless of type, has somehow become categorized as if they were posts. To clarify, if I go to Pages, it is empty. Testimonials, the same, and so on. But when I go to click on Posts, all of that missing content is there (though a little wonky). At the same time this started, all of our log-ins wouldn’t work until we reset the password. It’s like something really messed up a lot of the database or something related…

Affected pages:
sarasota.home-tech.com
agents.home-tech.com
Example of a currently functional one:
home-tech.com

The man in charge of keeping the website up-to-date left for vacation, but before he left he upgraded WordPress and the theme.

Another recent change was (we use Genesis) I needed to make a custom post type and the child theme did not have a single.php, so I created it for that specific theme, and only in that one child theme (the one sarasota.home-tech.com uses). I created the new single.php just over a week ago, whereas the problem I am posting about started, at the very most, two days ago.

So far I have tried switching to the twentyfifteen theme to see if the problem was theme-related, but it persisted. And I also deactivated all plugins with no luck there either.

Any suggestions at all would be very appreciated!

Here’s the code for single.php that I created just in case that is relevant.

<?php
/**
 * This file adds the Home Page to the Magazine Pro Child Theme.
 */

add_action( 'genesis_meta', 'magazine_home_genesis_meta' );
/**
 * Add widget support for homepage. If no widgets active, display the default loop.
 *
 */
function magazine_home_genesis_meta() {
	if ( is_active_sidebar( 'home-top' ) ) {
		// Force content-sidebar layout setting
		add_filter( 'genesis_site_layout', '__genesis_return_content_sidebar' );
		// Add magazine-home body class
		add_filter( 'body_class', 'magazine_body_class' );
		// Remove the default Genesis loop
		remove_action( 'genesis_loop', 'genesis_do_loop' );
		// Add homepage widgets
		add_action( 'genesis_loop', 'magazine_homepage_widgets' );
		// Remove the default Genesis loop
		add_action( 'genesis_loop', 'genesis_do_loop' );
	}
}

function magazine_body_class( $classes ) {

	$classes[] = 'magazine-home';
	return $classes;
}

function magazine_homepage_widgets() {
	genesis_widget_area( 'home-top', array(
		'before' => '<div class="home-top widget-area">',
		'after'  => '</div>',
	) );
}
genesis();