Does this still happen if you do not use ray tracing? What is your source image? In P5 a bump strength of 0.1 is VERY high (0.001 to 0.03 is the average range), particularly if your bump source image has anything other than a black background, such a high setting may cause a problem. This also could be a displacement issue, so try it with displacement turned off and a lower bump strength and see what happens.