Deflector special item now reduces stun duration from Garrison attacks. The amount of reduction is based on the Deflector's rarity:
Common Deflector stun duration = Normal Duration / 1
Uncommon Deflector stun duration = Normal Duration / 2
Rare Deflector stun duration = Normal Duration / 3
Ultra Rare Deflector stun duration = Normal Duration / 4
Legendary Deflector stun duration = Normal Duration / 5
Precursor Deflector stun duration = Normal Duration / 6
Ultimate Deflector stun duration = Normal Duration / 7

A Rare Deflector, for example, would reduce a 12-second Garrison stun to 4 seconds.
Deflectors were not seeing much use, and stun stacking made garrison busting borderline impossible when taken to an extreme.