Dedra Coliseum bug: Undermine not triggering on expose as described

Mosmos pinged MeatheadMilitia to report a Coliseum bug involving Dedra:

• Dedra's kit is supposed to inflict Undermine on allies who trigger Expose on the enemy.
• In Coliseum, the hero ability exposes the boss every turn, so by the kit text every ally hit on the exposed boss should apply Undermine.
• In practice, the Undermine application is not firing.

MeatheadMilitia replied: "Lemme go see if i've passed this one along yet." No confirmation of whether the bug has been escalated or whether a fix is in flight was given on this day.