The likely case is that you duplicated a block marked as detail and didn't move it thus you have two exactly identical blocks in the same spot. I've intersected detail blocks before (nearly 16 months ago). To fix this problem, just go to find object in one of the menus in WED and search for block 2 or 64.
As to the case of a block with inconsistant surfaces, the cause to this is that you may have a "shaded" flag mixed in with a "turbulance" or "sky" flag for the block. The best I can think of for finding this suspect block is to use the select tool and select blocks so that a different flag is set than expected. Other than that, I don't know how else to find such a block without the block number being noted.