Sorry, hit enter too early. The last sentence above suggests that even if the problem is resolved in Inkscape it may very well still not work in PPT. I have noticed in some other contexts that PPT occasionally has issues with lines that it does not have with filled shapes. For instance, PPT 2010 does not respect the simplest line width parameter in EMF files. If MATLAB can be configured to generate solid lines (polygons with fill, without stroke) those might work better.
Sorry, hit enter too early. The last sentence above suggests that even if the problem is resolved in Inkscape it may very well still not work in PPT. I have noticed in some other contexts that PPT occasionally has issues with lines that it does not have with filled shapes. For instance, PPT 2010 does not respect the simplest line width parameter in EMF files. If MATLAB can be configured to generate solid lines (polygons with fill, without stroke) those might work better.