**System Information**
Win7 Ult x64 Sp1 + GeForce 880 GTS 512
Similar result on another (newer) machine with Win8.
**Blender Version**
Broken: 2.71, 2.70
Worked: 2.69 (supposedly based on blendernpr.org tutorial)
**Short description of error**
In freestyle, all splitting options work normally except for 'Material Boundary'.
**Exact steps for others to reproduce the error**
With Freestyle activated and the following setup in Properties > Render Layers > Freestyle Line Style.
Chaining checked, all others unchecked
+ Thickness modifier 'Along Stroke'.
Checking Material Boundary seems to split some lines at angles even when min and max 2d angle are deactivated.
Test file available for 7 days on
http://wikisend.com/download/479784/NPR_MatBoundBug.blend