I could swear that one of the nodes in Umbral Blades says that the spinning blade will move the desired cursor location, spin, and explode (paraphrasing). However, when I have the mouse over a target and cast Umbral Blades, the blade is cast beyond that point thus landing behind the target location.
Yeah Precision Cuts makes throwing UB better for sure but its still off and bugged for many years.
The homing node and explosion range helps against that awful aiming.