Edge Waves still have vorticity

Ok so I got fixed the code and now I can run the example edge wave case in linear and nonlinear mode. I put the figures below; LEFT is LINEAR and RIGHT is NONLINEAR. The color in the plot is vorticity NOT setup and the colorbar is +/- 0.0005 (small but on the order of what we think is contaminating the balances from the other cases).



This answers two of the possibilities I think. First it says that nonlinearity is not what is giving the edge waves their vorticity. Second I believe it also says that they don't have vorticity due to no having one exact edge wave wavelength in the domain. Of course I eliminated possibilites but still have no idea what it is. Relationship to set up or something? Also its subtle but the shape of the edge waves is different between the two cases.