I thought using GL_DYNAMIC_READ for my instancing uniform buffers would be preferable to GL_STATIC_READ, but I eventually tracked a bug down to it, which would cause black triangles to appear, and sometimes vertices would be positioned incorrectly.


on what platform, graphics hardware and driver version?

Windows XP Pro, NVidia GE Force 8800 GTS 320, 169.21 (latest public driver as of now).