This skill counts itself as 'recharging' when calculating bonus damage. Using this without other Beast Mastery skills still gives the bonus damage x1. Ideally, only three other Beast Mastery skills are needed in order to get the max +80 damage bonus if your Beast Mastery is at least at level 13.
Other skills needed
Skills that disable non-attack skills upon use (like Tiger's Fury) will then allow Enraged Lunge to include the damage bonus from other Beast Mastery skills not commonly 'recharging' due to fast or no recharge times for those skills (like Charm Animal and Comfort Animal for example).
Bonus damage is calculated based on the number of skills recharging when Enraged Lunge is activated, not when the attack is made.
The description for this skill appears incorrectly under the pet's effects monitor.