Kindred Double hunt

Noticed this while on ARAM, occasionally Kindred's hunt will be scored, but her prey holds onto the mark, allowing kindred to get two stacks.

Most recent game I noticed Kindred on purple side with Ahri marked as prey. Kindred had BOTRK and Hexdrinker. Kindred kills Ahri, gets stack and Ahri remains marked. Second time Ahri dies, mark is consumed and another stack is awarded.

I'm having a hard time recreating due to the nature of ARAM, can't seem to get it on SR (but it may be there). It seems to happen every other game or so when I get Kindred (hard to notice when someone else is them).