Everest, the Ice Kaiser

1 Tuner + 2 or more non-Tuner monsters 
Must by Synchro Summoned and cannot be Special Summoned by other ways. When this card is Synchro Summoned: Target 1 Set Spell/Trap Card on the field. Until your 2nd End Phase after this card was Synchro Summoned, those cards cannot be activated. Cards and effects cannot be activated in response to this effect.

To

1 Tuner + 2 or more non-Tuner monsters 
Must by Synchro Summoned and cannot be Special Summoned by other ways. When this card is Synchro Summoned: Target 1 Set Spell/Trap Card on both sides of the field. Until your 2nd End Phase after this card was Synchro Summoned, those cards cannot be activated. Cards and effects cannot be activated in response to this effect.

This guy had the wrong effect.

This would be a nerf... but why? Going through the trouble of synching 3 monsters for a level 10 should allow you to at least lock down 1 spell/trap card of your choosing.