The specs are stated with 1.5% threshold. So i think that it needs to be over this before it is regarded as a defect.
You need to see how many pixels are affected, over the total number of pixels on the CCD. If its over 1.5% then you may have a case.
Though if its under 1.5%, it may well be within limits.
Have a read here :
http://www.cloudynights.com/ubbthrea...8/Main/4973764
Theo