Update #2 - brand new coil arrived today, installed the 1,8 ohm, primed generously and it vapes great. I can only conclude that you have to prime the coil really really well. I'm vaping steadily on 1,84 ohms / 4,7 V / 12,5 W. The only thing now is to wait until my sense of taste comes back to life after years of smoking cigs haha