How do you fix this polygon glitch generated by fill3?

In the pictures below you can see blue rectangles plotted using fill3. You can see that when the data is plotted as part of the main figure a glitch appears where the rectangle appears to enter itself. When this data (attached at XYZ.mat) is plotted on its own using fill3 it does not glitch (second picture).

Could anyone explain why this is happening and either how to fix it, or a different technique I could use to produce the correct result?

Sample data

X =[

    1.7566   , 1.7559,    1.7552,    1.7543 ,   1.7538,    1.7531,    1.7523,    1.7532;
    1.7775   , 1.7768 ,   1.7328 ,   1.7758  ,  1.7752 ,   1.7307 ,   1.7743 ,   1.7754;
    1.7768    ,1.7328  ,  1.7758  ,  1.7752   , 1.7307  ,  1.7743  ,  1.7754  ,  1.7349;
    1.7559,    1.7552   , 1.7543   , 1.7538    ,1.7531   , 1.7523   , 1.7532   , 1.7567]

Y =[

    4.4285 ,   4.4278,    4.4275,    4.4270,    4.4267,    4.4261,    4.4258,    4.4265;
    4.4148  ,  4.4142 ,   4.4164 ,   4.4143 ,   4.4139 ,   4.4150 ,   4.4139 ,   4.4150;
    4.4142   , 4.4164  ,  4.4143  ,  4.4139  ,  4.4150  ,  4.4139  ,  4.4150  ,  4.4170;
    4.4278   , 4.4275   , 4.4270   , 4.4267   , 4.4261   , 4.4258   , 4.4265   , 4.4285]

Z =[

         0,    0.0278,    0.0552,    0.1000,    0.1267,    0.1531,    0.2000,    0.2265;
    0.0001 ,   0.0281 ,   0.0546 ,   0.1003 ,   0.1270 ,   0.1523 ,   0.2000 ,   0.2255;
    0.0281  ,  0.0546  ,  0.1003  ,  0.1270  ,  0.1523  ,  0.2000  ,  0.2255  ,  0.2609;
    0.0278   , 0.0552   , 0.1000   , 0.1267   , 0.1531   , 0.2000   , 0.2265   , 0.2567]

fill3(X,Y,Z,'b')

[Laurence hutton-smith]

XYZ.mat