Hmm, I guess I never got a look at it like that with the cover off while rotating the crank. If the tensioner is new and the internal spring is not broken, then I'd guess that it is normal. How much force would you guess that it took to push the expanded tensioner in against the rail/chain? I want to say that it usually takes on the order of 25lbs to get the cap's threads in place to start engaging when installing one (I have not measured it, it's just a guess about how hard I was pushing).
Does the rail move when the cam lobes get past peak lift and the lifter bucket is able to rotate the cams forward because of the valve spring force?