I have encountered chinese font rendering artifact in many SAMSUNG android phones when rendering large and bold chinese characters using Qt-android 5.3.1
The attached qtquick based sample program can reproduce this issue.

I can also produce this issue with QPainterPath, but if I draw the font path with Qt::WindingFill fill rule the artifact was gone. It seems that the path read from the chinese font glyph has intersection which will cause the artifact when filling with the default Qt::OddEvenFill rule.
I think the chinese font installed in SAMSUNG phone is special compared to other phone, I am not sure whether this is a bug of SAMSUNG phone or Qt font handling.