Today, I killed my teammate in a Custom Game

I was playing and my teammate was . She was being murdered by a tank in the river bush at top lane. I was running towards them and used my Q and E. and died at the same time, and I was credited with a double kill and 600 gold. I've read similar stories on the forums and I think it's some sort of bug in the patch. I haven't been able to replicate the incident since then.