Hi pglatz-dev,
I will admit that I'm not entirely sure of what you are saying is occurring.
Relay Response does not display a page. It returns a NVP response to your specified URL. This URL should be non-parameterized, should not use a re-direct and should be publicly accessible as well as return an HTTP 200 response before writing to the page or running any other script or executibles on your server.
What it sounds like you are doing is using a Receipt Link URL on the Authorize.Net Hosted Receipt Page to allow the end-user to navigate back to your server. If so, a bit more detail would be required to identify what the issue is exactly. I would suggest providing the field NVPs that you are including in your POST to the hosted payment form, minus any secure data (like credit card, exp date, or your Transaction Key) if you need further direction on where the cause of the issue.
Thank you,
Elaine