I found this thread after noticing the same problem. To one of the posters above. The tool tip does not say it doesn't work on strong targets. "Delivers a powerful knife attack to a vulnerable target, Dealing xxxx - xxxx kinetic damage to weak and standard targets, and xxxx - xxxx damage to strong targets. Only usable on incapacitated targets." Strong targets are the Gold and silver elites correct? Above it clearly states it should damage them. So Bioware another unpatched BUG? Or are the Gold, champtions and player characters in another class above strong?