Yeah. I'm afraid I'm not familiar with your specific issue, I'm just trying to give some suggestions since this board tends to be a bit stingy with replies depending on the question. (I still haven't heard any sort of reply to either of my last two questions).
I know this sounds weird, but I do remember a little while back having issues with nParticles calculating when the hypershade window was open (don't remember what Maya version it was). If I remember correctly, they didn't calculate at all and since yours are at least emitting, that probably isn't it either, but it's easy to check. So if your hypershade is open, I would close it down and see if that helps anything.
In order to replicate what happens in your video, I would need to check "Ignore Solver Gravity" on the particle object and then cut the "Away From Center" on the emitter down to zero. So if it is happening to you without doing those things, I assume it is some sort of bug? (Hence the "weird" suggestions I gave) So perhaps updating Maya (if possible) could solve it?
I'm sorry I'm not more help. Hopefully somebody smarter than I am responds to you.
Good luck! I hope you can figure it out.