These TCG rulings were issued by Upper Deck Entertainment and have since been deemed unofficial by Konami. They were previously considered official and can still be correct, as long as they follow the official gameplay rules, or unless Konami has issued a ruling that says otherwise. References: 
"Maju Garzett"'s ATK will be 0 if you Special Summon it, or Tribute Summon it with a monster with "?" ATK (such as "Gradius' Option" or another "Maju Garzett"), or Tribute Summon it with only 1 Tribute using "Cost Down", or equip it with "Megamorph", or if it's flipped face-down and then face-up again, or if you Tribute Summon it with Mirage Tokens, or if you remove it from play with "Dimensionhole" and it returns to the field.
Shrink: If “Shrink” affects a monster whose original ATK is set by its effect when it is Summoned, like “Maju Garzette” [sic], ... that monster’s ATK will become 0, and remain 0 even after the effect of “Shrink” wears off.