Guild Wars 2

Description: When both Vampiric Rituals and Bloodthirst are selected from the necromancer’s blood trait line, lifesteal effects procced by wells are actually reduced instead of increased. This applies to both the on hit lifesteal granted by the Vampiric minor as well as the lifesteal granted by Vampiric Rituals.

Replication: Enter Heart of the mists and equip the ritual mastery trait. Use any well and note the lifesteal numbers from Vampiric Rituals/Vampiric. Then equip the bloodthirst trait and note how the numbers actually get smaller.

EDIT: I mistook ritual mastery for vampiric rituals. This has since been corrected. It is Vampiric Rituals that causes the bug when used in conjunction with Bloodthirst.

The screenshot confirms the above. The “19” is the siphon damage from Well of Corruption is from having both equipped. The “40” is the siphon damage from having removed bloodthirst.