Fixes: U4-4419 TempData is not being cleared on RedirectToCurrentUmbracoPage - it actually shouldn't be cleared but we need to handle how we add it properly as tempdata only clears when it is read

src/Umbraco.Web/Controllers/UmbLoginStatusController.cs

@@ -30,7 +30,7 @@ namespace Umbraco.Web.Controllers
             }
 
             //redirect to current page by default
-            TempData.Add("LogoutSuccess", true);
+            TempData["LogoutSuccess"] = true;            
             return RedirectToCurrentUmbracoPage();
         }
     }