Warwick's Q and luden's echo [gameplay]

Warwick's Q is suppose to heal him for 80% of the damage he deals with it. i practiced in a custom game when i started having inconsistencies. When the triggered passive of Luden's echo goes off Warwick's Q heals him for like 1/3 of the amount for some reason. This bug only occurs when the passive goes off at 100 stacks. any other time the Q still heals him for the full amount. to recreate this all you need is Luden's echo, take some damage so you can visibly notice the healing amount if the numbers are too small. Activate his Q on a minion with and without those 100 stacks and the amount healed will be different.