I'm not entirely sure if this is an oversight or an intentional design choice, but I decided to try Flechette Storm for a Strike mission and noticed that the first initial volley won't create Tangles when a target is killed, but will only create Tangles on the last volley if it kills a target. I'm not sure if this is a design choice or an unintentional interaction but I thought it was worth reporting as it can create some confusion with other players as much as it did with me.