In the PTR - both Firewalkers lave path and the trail of Cinders Rune will create traps while wearing Nats Set. If this is working as intended that is fine.
However this makes using Custom Trigger Rune for Spike Traps completely useless.
As i can understand is the Fire Dmg that trigger not necessarily fire skill , it could be even fire dmg on weapon , as i understand but Mods could explain better if than is not how i think it is.