Leyline of Punishment can be overridden [Investigating]

Leyline of Punishment reads, "While this support is on the board, each creature and Planeswalker loses Prevent Damage."

In practice, Leyline of Punishment actually seems to just remove Prevent Damage from anything which has Prevent Damage when the Leyline comes into play. Cards which grant Prevent Damage after the Leyline is already in play - for example, Tajic, Legion's Edge, or an Angel of Grace that is summoned after the Leyline is already out - are able to give out Prevent Damage without the Leyline preventing it.