Oh well, we're all in this together - so we'll all keep an eye on things and report back here ;-)
I definitely see the same symptoms as you though. Maybe it doesn't have to do with the offset buffers then, or maybe it's something particular to each one of our PCs.
 
So, when you get the problem, you change your settings and then go back to the exact same settings? And then it's OK?
Because that's what I was seeing - before I disabled the 64 bit engine.
Now I get the distortion occasionally - but that usually (I think) comes when I'm not using 64/48 or 128/48.
(this isn't scientific - but I think that's what's happening)