I've had this edge for maybe 30 hours of playing time now, and have been in many fights with 2 or more (sometimes 10 or more) creatures and have never seen shield riposte kick in and hit somebody other than the person I am fighting.

My shield jab is at 96% right now, and my dex is always maxed out at 23. Can somebody check this skill to make sure it does something?

If it is working as intended and is supposed to be a once-in-a-lifetime type edge, maybe the helpfile could be changed to reflect that, since "may rain shield jabs down on all who fight them" is not a very accurate description of this edge.