Since they upgraded pinging Kaisa ult to tell you if you're in range of people

It will no longer ping that you do not have enough mana for her ult. I had someone get themselves killed because I tried pinging that I couldn't join with my ult because I didn't have enough mana, but my ping told them I was in range instead.

I'm not sure if this is a bug, but seemed the best place to put it.