Unique item Drillneck Penetrating Quiver does not provide stated attack speed stat

The unique quiver Drillneck Penetrating Quiver rolls with an attack speed modifier between (8%-12%). However, when equipped the player's attack speed is not modified at all.

I've double checked that it wasn't an issue with my character by equipping a rare Penetrating Quiver with the same attack speed roll as the Drillneck Quiver, and my character's attacks per second is affected as expected when equipping the rare quiver.

The lack of attack speed effect from Drillneck can both be seen in skill tooltips and felt when visually comparing attacks between the Drillneck Quiver and the rare Penetrating Quiver with the same attack speed modifier roll.