Two for flinching

This is quite an expensive edge. It is the expense of the edge that brings me to the bug board as I am sure it must be a bug that has me suckerhit over 100 times and only seen the edge give me two sucker hits twice. The faceslash edge (slasher) is pretty consistent in its delivery of the second hit off the faceslash but two for flinching seems buggy or worth looking at the success criteria. I have sucker at 100% and as a duergar thief I am as strong a thief as you get to meet the requirements of the edge. Could you look into it please because at the moment it seems like a real waste of edge points. Thanks