The problem is that you are using meshgrid() on CollarPlanE and ...N directly. Since those vectors are not sorted, the mesh grid you're creating isn't sorted either, causing the strange twisting in the graph.
Instead, define an equally spaced and sorted vectors for x and y that you want to plot over, then do the meshgrid on those.
Also, as an aside, when you paste your code in the question, highlight all the code and click the "{}Code" button to make sure the formatting is preserved.
cla
F = scatteredInterpolant(CollarPlanE,CollarPlanN,AverageofMWDS_prate,'linear');
x = linspace(min(CollarPlanE),max(CollarPlanE),101);
y = linspace(min(CollarPlanN),max(CollarPlanN),101);
[yy,xx]=meshgrid(y,x); zz = F(xx,yy);
[~, hC] = contourf(xx,yy,zz,10);
set(hC,'LineStyle','none');
colormap jet
set(gcf,'color','w');
c = colorbar('Fontsize',16,'FontName', 'Arial');
c.Label.String = 'Penetration Rate(m/min)';
title('Average Penetration Rate Rd 48a Bench 11160','Fontsize',20,...
'FontWeight','bold','FontName', 'Arial');
xlabel('Grid E','FontSize',16,'FontName', 'Arial');
ylabel('Grid N','FontSize',16,'FontName', 'Arial');
xlim([7565 7685]); ylim([4905 4980]);
hold on
x = CollarPlanE;
y = CollarPlanN;
scatter(x,y,'MarkerEdgeColor',[0 .5 .5],...
'MarkerFaceColor',[1 0 0],...
'LineWidth',1.5);
a = RowLabels;
b = num2str(a);
c = cellstr(b);
dx = 1;
dy = -3; % displacement so the text does not overlay the data points text(x+dx, y+dy, c);
