Cycles Path Tracing stall or weirdness WTF?


I can’t tell if I have a glitch or what?

So I’m trying a 3000 pass render in cycles with three render layers.
Something weird happens. I’m using 2.6.2 official Mac 64 bit.

I looked at the render and the path tracer was at 635/3000, the UV editor was set to display the primary render layer, and the model and render were showing the live updates. I checked the other render layers, and they were blank as of yet (expected) and so I switched back to the primary layer and went to work in another program. When I go back the program that layer shows nothing an the path tracing count was lo. I figured it was working on the other layer. but now they are all blank. The time elapsed is 00:00 (it’s been going for an hour) but when I click or scroll, suddenly the path count jumps up. Seemingly each click makes the number go up. No image update. The render progress bar is still running. It doesn’t seem like Blender has crashed. it seems like it’s not updating. If the path coun’t didn’t change when I clicked, I might think it had crashed. But it seems like it’s all ticking away. as I write this, I go back and click again and get a big jump in the path count. So I dunnoh, has anyone else hit this? is this expected behavior?

well. I guess it just wasn’t updating. The render ended up finishing and compositing. After compositing though it seemed to partially freeze Blender. whatever. at least I got the render results.