Okay, yeah, I can fix that. But why would you want to take a feat that is less powerful than the Archetype?
when I asked my DM he said both could happen at the same time (sneak attack damage from archetype as standard action and then the feat as a swift action)
Generous GM. Considering UC came out well before the Strangler, I'd have ruled you can't double up, being a bit OP. Strangler grants the Sneak Attack as part of a complete Action, the feat which was before that archetype only adds Sneak Attack as a Swift action.
Anyways, this is fixed.