The new UA, Unearthed Arcana: Draconic Options, introduces a 6th-level spell called Fizban's platinum shield that can be cast on a creature within 60 feet of the caster, granting them a few benefits. The description of the final benefit reads as follows:
- If the creature is subjected to an effect that allows it to make a Dexterity saving throw to take only half damage, the creature instead takes no damage if it succeeds on the saving throw, and only half damage if it fails.
Since this spell benefit and Evasion have the same effect but different names from different sources, would they stack with each other?
For instance, in the case of a 7th-level monk failing a Dex save against the fireball spell while under the effect of this spell, would they take a quarter damage?