Adjust contour interpolation in plot

Hello!

Is it possible to adjust the interpolation of a contour plot? The issue I am having is that there are strange connections between points, indicated by the arrow in the image below, that I feel "should not be" the case. Though perhaps that conclusion is incorrect?

I have attached the data, included the script, and inserted the output image here.

Thank you for any help!

%CREATEFIGURE(X, Y1, Z, X1)
%  X:  contour x
%  Y:  contour y
%  Z:  contour z
%  X1:  vector of x data

% Create figure
figure1 = figure('Colormap',...
    [1.0000    1.0000    1.0000;
    0.9800    0.9800    1.0000
    0.9167    0.9167    1.0000
    0.8533    0.8533    1.0000
    0.7900    0.7900    1.0000
    0.7267    0.7267    1.0000
    0.6633    0.6633    1.0000
    0.6000    0.6000    1.0000
    0.4812    0.5617    0.9766
    0.4711    0.5665    0.9795
    0.4609    0.5713    0.9825
    0.4507    0.5761    0.9854
    0.4406    0.5809    0.9883
    0.4305    0.5856    0.9912
    0.4203    0.5904    0.9941
    0.4101    0.5952    0.9971
    0.4000    0.6000    1.0000
    0.3466    0.5867    0.9719
    0.2931    0.5733    0.9437
    0.2397    0.5600    0.9156
    0.1862    0.5467    0.8875
    0.1328    0.5333    0.8593
    0.0793    0.5200    0.8312
    0.0749    0.5375    0.8263
    0.0628    0.5566    0.8231
    0.0507    0.5756    0.8199
    0.0386    0.5946    0.8167
    0.0265    0.6137    0.8135
    0.0265    0.6209    0.8060
    0.0266    0.6281    0.7984
    0.0266    0.6353    0.7909
    0.0266    0.6426    0.7833
    0.0266    0.6498    0.7758
    0.0267    0.6570    0.7682
    0.0267    0.6642    0.7607
    0.0384    0.6743    0.7436
    0.1152    0.6949    0.6895
    0.1920    0.7156    0.6355
    0.2688    0.7362    0.5814
    0.3456    0.7568    0.5274
    0.4223    0.7774    0.4733
    0.4991    0.7980    0.4192
    0.5759    0.8187    0.3652
    0.6527    0.8393    0.3111
    0.6715    0.8444    0.2979
    0.6903    0.8494    0.2846
    0.7091    0.8545    0.2714
    0.7279    0.8595    0.2581
    0.7467    0.8646    0.2449
    0.7655    0.8696    0.2316
    0.7843    0.8747    0.2184
    0.8136    0.8817    0.1979
    0.8429    0.8888    0.1774
    0.8722    0.8959    0.1569
    0.9015    0.9029    0.1365
    0.9308    0.9100    0.1160
    0.9601    0.9170    0.0955
    0.9611    0.8977    0.0983
    0.9633    0.8576    0.1041
    0.9656    0.8175    0.1100
    0.9678    0.7774    0.1158
    0.9785    0.7183    0.1439
    0.9893    0.6591    0.1719
    1.0000    0.6000    0.2000]);

% Create axes
axes1 = axes('Parent',figure1,'BoxStyle','full','Layer','top');
box(axes1,'on');
hold(axes1,'on');

% Create contour
contourf(GRx,GRy,GRz,'LevelStep',1);


% Create colorbar
h = colorbar('peer',axes1);
set(h, 'Limits', [0 12],'FontName', 'Arial', 'FontSize', 18,...
    'FontWeight','bold','Color','k')
caxis([0 12])
hold on

%Plot data points on top of contour plot
plot(GRx,GRy,'k.','MarkerSize', 5)
set(gca, 'FontName', 'Arial', 'FontSize', 18)
xlim([5 50])
ylim([100 1550])
set(gca, 'XTick', [0 5 10 15 20 25 30 35 40 45 50],...
    'XScale', 'linear',...
    'YTick', [250 500 750 1000 1250 1500],...
    'YScale', 'linear',...
    'Ycolor',[0 0 0],... 
    'Xcolor',[0 0 0],... 
    'FontSize', 18,...
    'FontName', 'Arial');