ill let the image speak for itself, whys this happening?
(renders fine under adaptive qmc)
Since it is perfectly square, I assume you are using DR.
If it is DR, then it could be one of two things (or perhaps more):
1) Other computers/slave is not seeing the HDR or IR map.
2) If you are using plugins (such as colorcorrect), make sure they are installed on the other machines as well.
I have had his happen rendering on one machine. It was fixed by setting the max environment to black.
In my case, I copied the files locally to each machine.
Didn’t like reading over the network too well!
-- DJ
That’s a very strange thing…
I’ve had something similar happening when the IR map as set to bucket mode. If it is, try single frame mode.
crap this is really getting annoying, again same problem
adaptive subdiv just screws up with hdr
QMC is again fine
not using any GI so it cant be the IR map or bucket modes…
i just rendered a football field also where the lines flicker on and off cause i think a bucket simply skips it… this is very bad 
What is the cutoff value of the material there ?
Best regards,
nikki Candelero
default, i never touch that
Can you send us the scene , so we take a look, including the hdri.
< nikki@chaosgroup.com >
Best regards,
nikki Candelero
thanx, just send it to you 
Yep, as supposed.
Set the cutoff value of the ball material to 0.001 in the option rollout and it renders OK ! Just add 1 zero more.
Best regards,
nikk Candelero