I think it's the keep apart being random. You can turn the viewport % up to 100 and everything will play correctly in the viewport, but sometimes the particles disappear in the render. The blobmesh and material aren't even involved yet so that means it's somewhere in the particles. Adjusting the accel limit is what I've found to make the renderings more stable.
3ds Max 2009 SP1, 2010 SP1
Maya 2012
Windows 7 Professional 64-bit
Dual Intel Xeon E5520, 6 GB Ram
NVIDIA GeForce GTX 460 OC