So I faced Yugi Mutou in plat, then he summon Gandora and activy the effect and gain 1600 or 1800. In my hand only have swift gaia fierce knight. It attacked me directly. Then my turn i draw enemy controller, I set it so in normal situation I can summon swift gaia, but i cant. So is bug or other effect of Gandora?
Confirmed Access Denied skill since it does not allow you to Normal/Special summon Effect monsters nor use their effects. Your Swift Gaia is effect monster so, yep.
Yugi muto uses the skill access denied which states that neither player cant summon an effect monster and effects of effect monsters are blocked, for one turn.
Including effects of effect monsters that activate in the hand.
John
Lifeless