Cultivated Rearguard +Evasion Rating Modifier doesn't give Evasion Rating

I have the unique rearguard quiver that has a cultivated modifier of +140 evasion rating replacing the additional physical damage to attacks modifier and when I equip the quiver my character's evasion rating does not increase. I'm playing a Widowhail build so I'm expecting to get more than just the +140 from the quiver in regard to evasion rating, but I'm not getting any at all.