Amatsu Dungon prob

[Yumera]

I'm training a acolyte at the amatsu dungon against firelocks. When the hit me my health doens't go down until like 3-5 seconds later. Even if i hit my health it recovers my mp but my hp goes suddenly down with out being hit. This happens every time one hits me so i was wondering if thats a delay thing or if that area lags badly?