Jungle Item upgrade "Devourer" drops to 40% attack speed once bought.

Item description says 50% but once bought and hovered over in item slots it then says 40%. This has happened to me while buying the "Poacher's Knife" and the "Ranger's Trailblazer". not sure if the item is giving the full 50% or dropping to 40% like highlighted.

Update: Just tested this in custom game. Although it still says its giving 40% attack speed, when sold and replaced with Nashor's Tooth (which gives 50% attack speed) my attack speed still stayed the same to the thousandth decimal. So this is just a Visual bug, but a bug none the less.