I did not make the calculations to verify if it's working and just hidden or if it's not, cause i'm lazy, but I noticed anyway that there is no way to check the bonus from Katie's legendary quiver : http://imgur.com/a/Lv5bE.
As you can see on the image, Lovin', Huggin', Kissin' and Snugglin' are all activated (although Lovin' is not at full strength but i assume it shouldn't change anything for the buff), Lovebird is the effect provided by the legendary bow, but there is no indication that the quiver buff is active, no icon (the 1st one in the image being from Bubba) nor any text.
So if someone could check if the buff is bugged or if it's just lacking display, that would be great.

Thanks for your answer.