For me it works 10/10 times
It's important to tap 5 times
When you do it 6 times it doesn't work. But Kekpuker wrote about this too. Tap - on numpad
Looks like once the heart bleeds you can't stop it unless you change the zone or exit the game
Where I scrwed up: I was in a combat zone, exit the game, continued later and tapped + 5times again
Guess it was already saved from earlier and I killed myself. Shit happens
When you're not sure, be ready to exit the game quickly or change the zone
But always keep in mind you have to tap + 5x again whenever you change the zone