[Edi]

Checked the turn and yes, there is a shroud with a F9 bless, which is what causes all the trouble. That's why slay magic never triggers and if the attacks were always repelled (and which is why no damage from the main weapon itself) and since the oracle is fire immune, the flaming weapons do nothing to it.

So if there is indeed some bug with the elf bane, it needs testing without the bless bugs messing things up.