Discont command has also problems with removable discontinuities. When you try examples like this:

discont((x^3-2*x^2)/(x^2-2*x),x);

discont((x*(x^2-2*x))/(x^2-2*x),x);

it returns different results.  

Have you reinstalled Maple toolbox for Matlab (or Maple)?

Thanks to all of you for your comments. Based on the comments, I think it would be better to change the source code of discont command instead of using its results (to get really only real discontinuities).