how can i deal with UE render window's black edge?

Hi all,
I need to render a scene cube map for oculus rift. But cube map texture can’t use MSAA, and then i render a 1024 * 1024 window six times and merge six image to a cube.
But i found that the image which i rendered had black edge.

Why it has a black edge?In fact, i had render the window to 1026 * 1026, and then cut 1 pixel each edge because the UE render window has fixed black edge.
How can i deal with this?

Since this may be a bug, please post this question to the Answer Hub:
and include a link back to this post.


Thanks for your reply, I had post the message to your link.