diff --git a/src/js/contentscript-end.js b/src/js/contentscript-end.js
index a3134fc76..9e3e1a291 100644
--- a/src/js/contentscript-end.js
+++ b/src/js/contentscript-end.js
@@ -33,8 +33,13 @@
 
 // https://github.com/chrisaljoudi/uBlock/issues/464
 if ( document instanceof HTMLDocument === false ) {
-    //console.debug('contentscript-end.js > not a HTLMDocument');
-    return;
+    // https://github.com/chrisaljoudi/uBlock/issues/1528
+    if (
+        document instanceof XMLDocument === false ||
+        document.createElement('div') instanceof HTMLDivElement === false
+    ) {
+        return;
+    }
 }
 
 // I've seen this happens on Firefox
diff --git a/src/js/contentscript-start.js b/src/js/contentscript-start.js
index 6a8ceff2b..21931a3e1 100644
--- a/src/js/contentscript-start.js
+++ b/src/js/contentscript-start.js
@@ -36,8 +36,13 @@
 
 // https://github.com/chrisaljoudi/uBlock/issues/464
 if ( document instanceof HTMLDocument === false ) {
-    //console.debug('contentscript-start.js > not a HTLMDocument');
-    return;
+    // https://github.com/chrisaljoudi/uBlock/issues/1528
+    if (
+        document instanceof XMLDocument === false ||
+        document.createElement('div') instanceof HTMLDivElement === false
+    ) {
+        return;
+    }
 }
 
 // This can happen