Interesting. I have that exact rail and it does not exhibit any of the symptoms you are experiencing and I have it on a VFC E-series upper and VFC OE 14.5" barrel.
I dunno man, looks pretty straight to me. And I'm pretty picky about this type of stuff.
It does have keymod on the 3/6/9 o'clock positions plus it does allow for a gas tube so it's not the Madbull version.
Have you tried emailing John to report your issues. I'm sure he will be able to help you out.