DK Lava Whip Not Working Right

Wildberryjack

This skill is supposed to change to a more powerful attack if the target is off balance or immobilized. It was working before but for the past week and a half the skill does not change to the more powerful attack even when the target is immobilized or off balance. I've gotten the indicator that the target was off balance but nope, gotten the indicator that the target was immobilized, but nope. The skill won't change. It simply is not working anymore at all.