In game http://warlight.net/MultiPlayer?GameID=6356304, in turn 3 I have bad luck attacking Lycanitis with 3 against 2. Normally with 0% luck, it's 100% a winner.

Why did I have bad luck? No other enemy near, so that's not the problem.

Two turns later, turn 5. I attack Mazaca. Again bad luck.
Turn 8: I try to attack Tibium. Again bad luck.

The rounding mode is "weighted rounding" so when you make an attack of 3v2 with 0% luck you kill 3 times 0.6 = 1.8 armies. Obviously this result needs to be rounded, when the rounding mode is "straight round" then the fraction is rounded to the nearest whole number, in this case 2. That is what youre used to playing. With 'weighted' then you have a 20% chance of killing 1 defender and a 80% chance of killing 2.

Thanks!