I have an over-hung bar with two rollers on top and two offset to the right on the bottom.  All four rollers are set to 'no penetration' with the bar, respectively.  However, when I run the FEA with a load on the left-most roller in a downward direction I don't see equal and opposite forces among the contact sets.  I *should* see a downward force on the top left, downward on the top right, upward on the bottom left and zero on the bottom right (like the crude sketch below).

    o           o

-----------------------

            o             o

Instead I am seeing an upward force from the bottom right roller and zero on the bottom left.  Also, the forces don't balance.