Chandra Acolyte of Flame's -2 Loyalty Ability doesn't work with some alternate casting costs
Instants and Sorceries in the graveyard with Spectacle, Surge, and Overload cannot be cast for their alternate cost after being targeted with Chandra, Acolyte of Flame's -2 Loyalty ability.
Steps to Reproduce
1. Mel and Vorthos start a 2-player Test game.
2. Mel puts Fervant Champion, Light Up the Stage, and Chandra, Acolyte of Flame into hand.
3. Mel casts Fervant Champion and Light Up the Stage before combat.
4. Mel attacks Vorthos with Fervant Champion. Vorthos takes 1 damage.
5. Mel casts Chandra, Acolyte of Flame, then activates its third ability targeting Light Up the Stage. The ability begins to resolve.
You're prompted "Cast this without paying its mana cost? (Click to cast)". After clicking Light Up the Stage, the prompt states Pay 2R.
You're prompted "Cast this card? (Click to cast)". After clicking Light Up the Stage, you get a menu showing options to pay with spectacle (R) or not (2R).