At the moment, if Gaea's Blessing is milled with Ashiok's ability it interrupts the resolution of the effect and shuffles the graveyard. This is not how the rules interaction works, the entire ability of Ashiok should resolve including the exiling of the graveyard, after which the Gaea's Blessing trigger should be put on the stack with no graveyard left to shuffle back in, the player would then still shuffle their library.
At the moment, if Gaea's Blessing is milled with Ashiok's ability it interrupts the resolution of the effect and shuffles the graveyard. This is not how the rules interaction works, the entire ability of Ashiok should resolve including the exiling of the graveyard, after which the Gaea's Blessing trigger should be put on the stack with no graveyard left to shuffle back in, the player would then still shuffle their library.