Seems like Jsoup has a default limit (2Mb), whereas Jenkins pages can be bigger, especially when there's a huge queue.
diff --git a/src/main/java/org/apache/maven/dist/tools/JsoupRetry.java b/src/main/java/org/apache/maven/dist/tools/JsoupRetry.java
index 60f374d..04eb395 100644
--- a/src/main/java/org/apache/maven/dist/tools/JsoupRetry.java
+++ b/src/main/java/org/apache/maven/dist/tools/JsoupRetry.java
@@ -40,7 +40,7 @@
         {
             try
             {
-                return Jsoup.connect( url ).get();
+                return Jsoup.connect( url ).userAgent( "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:25.0) Gecko/20100101 Firefox/25.0" ).maxBodySize( 0 ).get();
             }
             catch ( IOException ioe )
             {