Given that the new Paladin SP deals damage and then adds effects, I wouldn't be at all surprised if that weird "additional effect accuracy" bug were cropping up. It is a very hard-working bug, and currently affects many weapon-skills and some blue magic.

If this industrious bug is affecting the new Paladin SP, the effect will be at full potency but will only activate 5% of the time or so. It seems weird that it would affect something meant to be 100%, but, it's weird that such a large-scale bug would even exist so I'm willing to entertain this possibility.

The next part is going to sound ridiculous, because it is ridiculous. The recast is 5 seconds on the test server, yeah? Is there something you could conveniently use the new SP on over and over and over? Even a zone with Incredibly Tough normal stuff would probably work, if popping the same Void Exhibitionist over and over is a pain.

Of course, I also won't be surprised if the new SP just isn't that good.