--- a/src/WrappedHttpHandler.php
+++ b/src/WrappedHttpHandler.php
@@ -171,6 +171,14 @@
         if (!isset($err['response'])) {
             $parts = ['response' => null];
             $serviceError .= $err['exception']->getMessage();
+        } elseif ($err['response']->getStatusCode() < 300) {
+            // A 2xx response attached to a transport-level rejection is a
+            // partial success payload (e.g. an interrupted streamed download),
+            // not an error document. Parsing it reads the entire body into one
+            // string and can exhaust memory_limit on multi-GB sink downloads.
+            // TODO: remove once https://github.com/aws/aws-sdk-php/issues/3319 is fixed.
+            $parts = ['response' => $err['response']];
+            $serviceError .= $err['exception']->getMessage();
         } else {
             try {
                 $parts = call_user_func(