A problem with the Mark of Nurgle

The Mark of Nurgle attribute says it adds the Poison contact effect. However, bile trolls, cultists of Nurgle, Bilious Thunderguff (RoR giant), Sons of the Last Plague (RoR chosen), and Bloab Rotspawned don't have Poison contact effects. Previously, this was because units couldn't stack multiple contact effects onto their attacks, but that is no longer the case.

Either these units should also inflict Poison, or the Mark of Nurgle description should get changed to include the case of units having alternate contact effects.