there is rubbing, however only in very extreme positions (not during a ride) - when I turn the baseball all the way to the right, it rubs slightly against the bento, which in turn prevents the basebar from returning to the straight position. I haven't noticed any difference between the gaps on the left and right.
I had that problem however with the original bento and stem (see picture below, sorry for the dirty bike), and Canyon sent me a free bento replacement (haven't had the chance to try it out, as I wanted to go with the lower bento and different stem anyway). Try re-installing the bento? It might be possible to move it ever so slightly backwards.