I'm not sure if this is a bug. Enemy jungler died clearing a jungle camp. I used hawkshot on the jungler before he started the camp. When he died to the camp I was awarded both gold and his red buff. There were also no other champion assists on the kill - it was only me.
My best guess is that this is intended behavior.
Back in patch 9.1, Ashe's hawkshot was changed so that it would grant assists if it reveals champions (if they would've been unseen without hawkshot) and the champions die within 10 seconds.
In the case of a jungle camp execution, your hawkshot probably 'tagged' the jungler for kill participation but since none of your allies were involved, you ultimately received the kill credit.
