Found additional usages for (var web = new HttpClient()) and replaced with private static readonly HttpClient HttpClient = new HttpClient();

src/Umbraco.Web/Editors/HelpController.cs

@@ -7,20 +7,18 @@ using System.Threading.Tasks;
 namespace Umbraco.Web.Editors
 {
     public class HelpController : UmbracoAuthorizedJsonController
-    {  
+    {
+        private static readonly HttpClient HttpClient = new HttpClient();
         public async Task<List<HelpPage>> GetContextHelpForPage(string section, string tree, string baseUrl = "https://our.umbraco.com")
         {
             var url = string.Format(baseUrl + "/Umbraco/Documentation/Lessons/GetContextHelpDocs?sectionAlias={0}&treeAlias={1}", section, tree);
-            using (var web = new HttpClient())
-            {
-                //fetch dashboard json and parse to JObject
-                var json = await web.GetStringAsync(url);
-                var result = JsonConvert.DeserializeObject<List<HelpPage>>(json);
-                if (result != null)
-                    return result;
+            //fetch dashboard json and parse to JObject
+            var json = await HttpClient.GetStringAsync(url);
+            var result = JsonConvert.DeserializeObject<List<HelpPage>>(json);
+            if (result != null)
+                return result;
 
-                return new List<HelpPage>();
-            }
+            return new List<HelpPage>();
         }
     }