I don't know if this is a recent bug or it existet for longer.

Killing your teammate earns you 250 XP.

If you abuse the system of instant revives, then you can kill your teammate over and over again to farm XP.

But: If you die and level up at the same time, you won't revive on your own and stay dead.

So, there are 2 bugs here. One is a gameplay decision that could lead to abuse and the other seems to be a bug when 2 events happen at the same time and throw off the game logic.