Setup: An actor with Negative Energy Being and Vulnerable attached (NEB older than Vulnerable) is damaged. What happens: NEB converts damage to healing, then Vulnerable increases the heal amount by 2. What I expected to happen: NEB converts damage to healing, then Vulnerable does not trigger because the effect is now healing, not damage. If this is the intended behavior, there is at least a text bug in the battle log (Misguided Heal was played). F. Van Gardner painfully heals Graceful Charm. Negative Energy Being converted damage to healing. Graceful Charm takes extra damage! Graceful Charm recovered 4 HP. Negative Energy Being converted healing to damage. Graceful Charm took 4 Holy damage. The issue is in lines 2, 3, and 4. A screenshot is attached: Spoiler: Screenshot EDIT: Pointed out where the issue occurs in the battle logs.
Problem is that the third line, "Graceful Charm takes extra damage", should come before the second line, "Negative Energy Being converted damage to healing". Because if NEB already changed the damage to healing then Vulnerable should not trigger afterwards.
Also, I just tested, and the damage from NEB gets treated as damage by both Vengeance and Boosted Heal. I suspect Vulnerable treats the healing from NEB as damage because Vulnerable and NEB are triggered in the same trigger phase. It seems odd that the initial damage only starts being treated as healing in the next trigger phase instead of immediately after NEB triggers.