Banner Bug with Gravebind

I love Banners, and i try to create a support but u dont get any Valour if u not kill with an Attack. That is decent ok.

But now comes the Bug:

If my Minion kill with an Attack i dont get Valour also even if i use "Gravebind Rope Cuffs"

Please fix it to go Banner any viable. I am the Pur Supporter and cant kill, and only Charges at Uniq Monster are to low.