Bonecraft not apparently working

I’m playing today’s release on Win10. The description for bone reapers says “After attacking an ally with less than 25% Health, kill it, then grant 50% of its Attack, Intelligence, and Defense to all your creatures.” I have twice killed a foe described as “Dying” with a bone reaper. There is no indication that any stats are being adjusted.

Frank.

This trait works when you kill one of your own creatures, not an enemy.

Thank you.

Frank.