Something wrong with contourm's fill functionality?

I am trying to plot contours of data on the robinson projection of the globe using R2015b. When I use 'on' for the fill property, the plot looks very bad:

When I don't turn on the fill property, the plot looks okay (the abrupt end of the contour lines at 30 degrees lat is due to only NaN's being present between 30 degrees and -30 degrees lat):

I have attached the datasets I used to produce the plot. Here's my code:

figure
proj = 'robinson';
orig = [0,0];
C = load('coast');
h_axes = axesm('MapProjection',proj,'origin',orig);
set(gcf,'color','w')
framem
[~,h_plot] = contourm(latGrid, lonGrid, data,'Fill','on','LevelList',contourLevels)

Can anyone explain why this happens and possibly a solution to the problem?

By the way, here's what the plot looks like using R2012b:

Thanks

[Walter Roberson]

The file did not get attached.

Which version of MATLAB are you using? I do not know how contourm is implemented but contour (non-map) has a completely different implementation as of R2014b.

[Vineel]

Sorry about that. Find it attached now. I am using R2015b.