The the plate mounted so that the rail is pointed towards the lens, back removal is no problem. I will have to check with it mounted the opposite way. The only issue with this is the camera has to be mounted to the smart flex back to front due to the stop screws. but if it's not done this way, then no lens other than the 80mm and older 35mm/45mmD can be moved to a nodal solution. The rail won't accommodate the 55mm LS without the re-positioning. I have not noticed any issues with it mounted this direction.
Edit, yes with the plate mounted so that the rail is pointed to the back, removal of the digital back is not easy, as the XF 90 degree finder is blocking from the top.
I have not had any issues with the plate bending using the way I am, even with the 35LS mounted. But I realize that it's more than likely putting a bit of strain on the plate.
Paul C