Basically the default U.glalphaclip was 1.8367099231598242e-40 in some computers (e.g., OSX 10.11, AMD Radeon HD 6750M) this value would need for bad gl clipping. The new default is 0.0. To test this before/after the fix, just run: $ blender -b --factory-startup --python-expr "import bpy; print(bpy.context.user_preferences.system.gl_clip_alpha)"