You NEED to fix the mortars in the Manning Zoo stronghold. There is quite literally no time to dodge the blast radius from the time the red circle appears and the hit. The first section they appear in has devolved into hiding in the hallway, while new players rush out and get destroyed. Players get left behind while revive hives reset, and it's just a mess. Either siignificantly reduce the damage, or extend the signal timer.
Signal to hit timer is roughly half the time of othet missions that include mortars.
Do a better job of play testing your patches. I'm pretty sure previous patch notes stated this was addressed in some way, so it either wasn't, or a subsequent patch broke it again.