pointLocation doesn't work for points on boundary edges.

pointLocation sometimes doesn't work for points on the boundary edge, but sometimes it does work. Is it a bug or am I missing anything? Code below:

TP= [0	0;1	0;0	0.55362;0.34043	0;0	1;0.32885	0.30133;0.24765	0.71525;0.21437	1;0.41137	0.54785;1	0.30028;1	0.52531;1	0.74369;1	1]
C=[7	3	5;7	8	5;6	3	7;6	9	7;11	10	6;11	9	6;1	3	6;1	4	6;4	6	10;4	2	10;11	9	7;11	12	7;12	7	8;12	13	8]
TR = triangulation(C,TP)
triplot(TR)
hold on
P=[0.3,1]
plot(P(:,1),P(:,2),'k*')
ID = pointLocation(TR,P) %output NaN
ID2 = pointLocation(TR,[0.301,1]) %output 14