Poison is not removing from mercenary

I am experiencing an issue where it appears my mercenary is forever poisoned. I go to Akara to heal, he stays green. He’s wearing cure, and the aura doesn’t remove the poison. At least the green silhouette is staying. Has anyone else experienced this? Wondering what is going on here.

Yes, it happens quite often actually.
I believe the condition for it to trigger is to have the merc’s current health reach max before the poison instance expires.
Not sure if it’s specific to regen or leech though, maybe both.