Apologies for the delay.
This has been identified as a known issue:
There are some known issues with the current release of Target.
- Unable to support editing on iframes having iframe buster code
Proxy cannot bypass contents on an iframe.
Please see the known issues doc for more.
I also see that you've already a support ticket (ticket number 150526-000129) for this query. I'll follow up with the support team to have an answer for you soon.
If I understood your query correctly when you try to simulate the experience live the correct experience does not render and the user is redirected to another page?
Can you let us know what you see if you try to preview this activity in Target Premium "View Experience URL"?