following a guide

i am following a guide https://poe.ninja/builds/settlers/character/ominous111/sir_francis_trickery?type=exp&i=0&search=class%3DAssassin%26skills%3DCobra%2BLash

i use a skill called automation to proc some deffence but now it only proc steelskin and not moltenshell at the same time whats going on ?

Those are guard skills, they share cooldown. It will proc only one of them.