Javascript replaces many page elements with user count

This patch is not able to make a difference, because the executed JS is limited to the #admin-menu context anyway already:

/**
 * Perform dynamic replacements in cached menu.
 */
Drupal.admin.behaviors.replacements = function (context, settings, $adminMenu) {
  for (var item in settings.admin_menu.replacements) {
    $(item, $adminMenu).html(settings.admin_menu.replacements[item]);
  }
}

Could this be the problem?

You are missing the semicolon after two functions you define in Drupal.behaviors:

Drupal.admin.behaviors.replacements
Drupal.admin.behaviors.destination

Which caused all kinds of things to go on the fritz on my site, from intermittently broken drag and dropping functionality to other issues.

My apologies if you're already corrected this problem.

Here's a patch:

--- admin_menu.js (saved version)
+++ (current document)
@@ -166,7 +166,7 @@
   for (var item in settings.admin_menu.replacements) {
     $(item, $adminMenu).html(settings.admin_menu.replacements[item]);
   }
-}
+};
 
 /**
  * Inject destination query strings for current page.
@@ -177,7 +177,7 @@
       this.search += (!this.search.length ? '?' : '&') + Drupal.settings.admin_menu.destination;
     });
   }
-}
+};
 
 /**
  * Apply JavaScript-based hovering behaviors.

Also noticed that the getCache function was also missing a semicolon.