XMLHTTPRequest has wrong responceText after redirect

I'm sending XHR to the server1. It sends some data, then redirects to the server2. I receive concatenated data from both servers.

In the attachment implementations of the serves on node.js with express module. The first server sends this string: "This is text from 1-st server", the second - "This is text from 2-nd server".
Using test qml application gives following result:
"Result: This is text from 1-st serverThis is text from 2-nd server"

When using Firefox or Chrome on the same url, I receive correct result:
"This is text from 2-nd server"