My opponent picked a Coalition Relic by Booster Tutor bug, but when the Relic was being cast, my opponent was able to activate the ability of Grist, and also I could not attack that Relic even though I could see the highlight on the Relic. Later, when another Coalition Relic is being cast from my opponent's hand, the first Relic suddenly turns to a Grist.
Happened in Vantage cupe.