Nightfall introduced jetstream things that intermittantly switch on and off and shoot out flames or cold-blasts to do damage and condition anyone stupid enough to walk past them while active...
Eye of the North also introduced similar things coming up from the ground... and poison-jets.
The issue is... A.I seems completely oblivious to them... for the most part. Flag herohench anywhere near one of these... and if enemies appear on the other side ... the herohench will quite happily leeroy right through the trap and potentially get themselves wiped.
I've been forced to stop just past one of these before to avoid aggro.... the pillar activated... and two henchies just stood in the damage-stream until they died.
Some sort of node needs to be added to these traps that the herohench AI can detect and seek to avoid (or move around) when it is active.... as in some areas it is getting quite ridiculous (Shards of Orr level 3 comes to mind).
Most of the time, moving arund like a swarm of bees is enough to prevent those proyectiles from traps hitting the party, but AI just stands there, while health goes down. They should 'kite' those proyectiles after the second hit.