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.
We thought that might have been it too but looking at combat logs, the damage taken did not add up to our healers' health. 1 Scoundrel only took a complete
total of 12k damage in one run and still managed to die. In another instance, I hit the wall after the pushback, went down to 10% HP and actually reached my designated shield before any of my group members and I had way less health than any of them. Additionally, we would have seen everyone get hit with an early Mortar Volley right after the pushback. This did not happen. Something was wrong.
Additionally, the red "-14,000" did not appear on my screen, leading us to believe I and the scoundrel was NOT hit by a Mortar Volley. It's certainly a strange thing. Using the pushback was a great way to reach the shields faster. Interesting and challenging to see this tactic possibly removed.
Trying the tanks again tonight. We've made it to the second shield phase and upped the DPS on Firebrand; we now do not get to a second DD.