It seems that when you ctrl to compare stat changes between a unique item and another item, it ignores everything except the intrinsic stats on the unique item e.g. for Riverbend Grasp (unique leather gloves) with +7 armor, + 25 void protection intrinsic mods, and +60% throwing da, +40 health, +100% increased dodge and 15% chance to throw axe, everything except the +7 armor and +25 void protection is ignored when using ctrl to compare stat changes with another glove.
Would include screen shot, but was unable to figure out how to take a windows screen shot while holding down the ctrl key 