On XB1 NA the initial cast of Piercing Mark IV procs Valkyn Skoria. Since Piercing Mark doesn't do damage, therefore isn't a DoT effect, I assume this is a bug.
Also, not sure if it is intended but Power Extraction IV only does damage if you are in combat. The ability still cast on a target if you are out of combat and you get major brutality if the target is hit, it just doesn't do damage