Defensive Systems: This gave us the biggest curve ball. In HM, both 8 and 16 groups, the tanks would do a push back in which we would usually use to get into shields faster (position yourself to get pushed almost into the shields). However, we experienced people taking fall damage and damage from hitting any walls from this pushback. Literally, the other healer and myself would - appear - to get 1 shot after crashing into a rocky wall or after landing. After making adjustments, we found that getting off the tanks immediately and moving away around 80% on the bosses, no one would take a ton of damage from the transition.
Could the damage be coming from the Mortar Volley itself?
Get KB-> Hit a wall ->Get hit by the Mortar AoE while trying to run under the shield.