I’ve also noticed that if you make the container height 80% of the width it works fine. Therefore giving it more space to work in for the labels. May help someone else.
Is there any way to reduce the size of the actual pie, and so give more space for labels?
On the fiddle there is loads of space available, like the segment that covers 240deg of the pie. Why is that one not showing?
I’ve also noticed that if I reduce the font size for the labels, more labels do appear.