This affects druids that are underwater. It is centered around the Celestial Avatar skill Cosmic Ray (CA1).
When hitting an enemy with the Cosmic Ray skill underwater, the Druid is given a stack of Lingering Light even if the trait is not selected.
Additionally, when the Druid selects the Grace of the Land trait, the alacrity boon will be applied to the enemy when struck by the Cosmic Ray skill.
None of the other Celestial Avatar skills have this issue of granting trait stacks or giving enemies boons, and it works as intended above water.
Picture showing the boon applied to enemy and stacks of the inactive trait