diff --git a/iocore/cache/CacheWrite.cc b/iocore/cache/CacheWrite.cc
index 48d16cb1f2b..b9bd8a546a7 100644
--- a/iocore/cache/CacheWrite.cc
+++ b/iocore/cache/CacheWrite.cc
@@ -106,7 +106,14 @@ CacheVC::updateVector(int /* event ATS_UNUSED */, Event * /* e ATS_UNUSED */)
          data should remain valid.
       */
       if (alternate_index >= 0) {
-        alternate.copy_frag_offsets_from(write_vector->get(alternate_index));
+        /*if length changed, fragment offset also need to change, if not cause range request error*/
+        if (total_len != uint64_t(write_vector->get(alternate_index)->object_size_get())) {
+          Debug("cache_update", "update length changed, new length:%lu, old length:%ld", total_len,
+                write_vector->get(alternate_index)->object_size_get());
+        } else {
+          /*do not copy everytimes, if data changed, this copy makes range request error*/
+          alternate.copy_frag_offsets_from(write_vector->get(alternate_index));
+        }
       }
       alternate_index = write_vector->insert(&alternate, alternate_index);
     }