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: 
When a Non-LIGHT monster’s effect is activated while the monster and “Light-Imprisoning Mirror” are both face-up on the field, if you chain “DNA Transplant” and select “LIGHT”, the monster’s effect will be negated if the monster is still face-up on the field when its effect resolves because it is now a LIGHT monster.
↑Konami Judge Program Rulings are considered unverified, as their source(s) are not publicly viewable. They are not confirmed as applicable to the TCG until they have been officially published by Konami.