using riggle and viblin for shaker simulation

Hello,
I am trying to simulate the ANSI/ASAE S424.1 test. This uses a crank to wiggle and move screens.

I have the following movements
variable per2 equal 1./5 # 2.4
fix mv_box1 all move/mesh mesh BotShear riggle origin 0.125 0.0625 0. axis 0. 0. 1. period ${per2} amplitude 5
fix mv_box2 all move/mesh mesh BotShear viblin axis 1. 0. 0. order 1 amplitude 0.015625 phase ${phase} period ${per2}

Right now I am testing with with a shear box geometry to figure out the commands...

I am experiencing it "walking" in the negative y direction.

I was able to get around this walking by adding a third move command
fix mv_box3 all move/mesh mesh BotShear linear 0.0 0.02 0.0

but I would not like to do it this way. Any help would be greatly appreciated.

I have also added the test case (finishes in about 10 seconds) if you would like to take a look at it.