diff --git a/lib/hooks/XMLHttpRequest.js b/lib/hooks/XMLHttpRequest.js
index b11ea4a40..e2d906b26 100644
--- a/lib/hooks/XMLHttpRequest.js
+++ b/lib/hooks/XMLHttpRequest.js
@@ -77,8 +77,8 @@ export function instrumentXMLHttpRequest() {
       return originalOpen.apply(xhr, arguments);
     }
 
-    const urlIgnored = state.ignored = isUrlIgnored(url);
-    if (urlIgnored) {
+    state.ignored = isUrlIgnored(url);
+    if (state.ignored) {
       if (DEBUG) {
         debug(
           'Not generating XHR beacon because it should be ignored according to user configuration. URL: ' + url
@@ -105,7 +105,7 @@ export function instrumentXMLHttpRequest() {
       'l': win.location.href,
       'm': method,
       'u': normalizeUrl(url),
-      'a': async ? 1 : 0,
+      'a': async === undefined || async ? 1 : 0,
       'st': 0,
       'e': undefined,
       'bc': state.setBackendCorrelationHeaders ? 1 : 0
@@ -158,6 +158,10 @@ export function instrumentXMLHttpRequest() {
     }
 
     function onError(e) {
+      if (state.ignored) {
+        return;
+      }
+
       let message = e && ((e.error && e.error.message) || e.message);
       if (typeof message === 'string') {
         beacon['e'] = message.substring(0, 300);
diff --git a/lib/transmission/formEncoded.js b/lib/transmission/formEncoded.js
index 54e3a6d2a..dad5d1876 100644
--- a/lib/transmission/formEncoded.js
+++ b/lib/transmission/formEncoded.js
@@ -16,8 +16,8 @@ export function sendBeacon(data: Beacon) {
 
   if (XMLHttpRequest && str.length > maxLengthForImgRequest) {
     const xhr = new XMLHttpRequest();
-    xhr.open('POST', String(vars.reportingUrl), true);
     disableMonitoringForXMLHttpRequest(xhr);
+    xhr.open('POST', String(vars.reportingUrl), true);
     xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded;charset=UTF-8');
     // Ensure that browsers do not try to automatically parse the response.
     xhr.responseType = 'text';
diff --git a/lib/vars.js b/lib/vars.js
index 70674a934..7150b5767 100644
--- a/lib/vars.js
+++ b/lib/vars.js
@@ -190,7 +190,7 @@ const defaultVars: {
   // eum('wrapTimers', true)
   wrapTimers: boolean,
 
-  // This key will be used by Weasel to privatelt store data ob objects.
+  // This key will be used by Weasel to privately store data on objects.
   // Make sure to change this key when deploying Weasel in production.
   secretPropertyKey: string,
 
@@ -214,7 +214,7 @@ const defaultVars: {
   highResTimestampReference: performance && performance.now ? performance.now() : 0,
   initializerExecutionTimestamp: now(),
   reportingUrl: null,
-  beaconBatchingTime: 500,
+  beaconBatchingTime: 0,
   apiKey: null,
   meta: {},
   ignoreUrls: [],