The description of a Spectator from the Lost Mine of Phandelver adventure says they have the following reaction (p. 62):
Spell Reflection. If the spectator makes a successful saving throw against a spell, or a spell misses it, the spectator can choose another creature within 30 feet of it that it can see. The spell affects the chosen creature instead of the spectator.
Does the target get a chance to save against the reflected spell, or is it an automatic hit?