seismic cry and endurance charges

if you use seismic cry and have an endurance charge to consume, if you stun another enemy you will override your current empowered attack stacks, even if you had more than what it would give, ie, you consumed an endurance charge and so you had 2 empowered attacks, but then stunned another enemy before attacking, you now only have 1 empowered attack.

Also if you search for Endurance in the gem bar, Seismic cry doesn't come up despite it having to do with endurance charges.

Thanks and God Bless