diff --git a/CHANGELOG.md b/CHANGELOG.md
index 08321edb0..0b3aadce2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ All notable changes to AET will be documented in this file.
 ## Unreleased
 **List of changes that are finished but not yet released in any final version.**
 
+- [PR-359](https://github.com/Cognifide/aet/pull/359) ([#351](https://github.com/Cognifide/aet/issues/351)) Disabled nu.validator language detection to fix random NPE
+
 ## Version 3.0.0
 
 
diff --git a/core/jobs/src/main/java/com/cognifide/aet/job/common/comparators/w3chtml5/wrapper/NuValidatorWrapper.java b/core/jobs/src/main/java/com/cognifide/aet/job/common/comparators/w3chtml5/wrapper/NuValidatorWrapper.java
index 3ef97acd6..7860ee7e7 100644
--- a/core/jobs/src/main/java/com/cognifide/aet/job/common/comparators/w3chtml5/wrapper/NuValidatorWrapper.java
+++ b/core/jobs/src/main/java/com/cognifide/aet/job/common/comparators/w3chtml5/wrapper/NuValidatorWrapper.java
@@ -55,7 +55,7 @@ public String validate(InputStream sourceStream) throws ProcessingException {
   private void setupAndValidate(InputStream sourceStream) throws ProcessingException {
     System.setProperty("nu.validator.datatype.warn", "true");
     out = new ByteArrayOutputStream();
-    validator = new SimpleDocumentValidator();
+    validator = createValidatorWithDisabledLanguageDetection();
     try {
       setup();
       validator.checkHtmlInputSource(new InputSource(sourceStream));
@@ -65,6 +65,13 @@ private void setupAndValidate(InputStream sourceStream) throws ProcessingExcepti
     }
   }
 
+  private SimpleDocumentValidator createValidatorWithDisabledLanguageDetection() {
+    boolean initializeLog4j = true;
+    boolean logUrls = true;
+    boolean enableLanguageDetection = false;
+    return new SimpleDocumentValidator(initializeLog4j, logUrls, enableLanguageDetection);
+  }
+
   private void setup() throws ProcessingException, SAXException {
     setErrorHandler();
     errorHandler.setHtml(true);