Ranger's Gait set - does it function in realtime?

TheYKcid

The 5th-piece bonus of the set is as follows:

(5 items) Reduce the effectiveness of snares applied to you by 50%.

What I'm curious about is whether this effect functions in realtime. Meaning to say, does it affect snares that were applied to my character before the set becomes active?

To illustrate this with an example:

1. I get snared (on my frontbar, where the 5pc bonus is absent)
2. I swap to my backbar (which consists of Ranger's Gait weapon/s, thereby activating the 5pc bonus)

In this scenario, will snares applied in the past become retroactively reduced when the 5pc becomes active?
Or does the 5pc have to be present at the instant the snare is applied, for it to take effect?