[2023] Armor on kill

Hi, sorry for low English.
My problem is like the headline. İ have 110k armor on kill stat but, i doesnt work when i have full health. i mean i cant see any blue bars stacking up, for 2-3 days. Before that it was working
i have 4 peace Striker and 2 peace Umbra green set.
What should i do , can u help me please