Rulings
Q1: You activate an effect that reads "Return 1 of your opponent's Digimon to their hand. Trash all of the digivolution cards of that Digimon" to return an opponent's Digimon to their hand. When your opponent's digivolution cards are trashed as a result, can you activate this card's effect?
No, you can't. "Trash all of the digivolution cards of those Digimon" is an explanation of what happens to the digivolution cards of the Digimon when it returns to their hand. It doesn't count as trashing digivolution for the purposes of this card's effect.
Data Sources
EN
Official English Card Listworld.digimoncard.com
Lv.3 Gomamon P-004 P Rookie | Vaccine | Sea Beast - --- Inherited: [Your Turn] [Once Per Turn] When you trash a digivolution card of 1 of your opponent's Digimon， gain 1 memory.
A
Official English (Asia) Card Listen.digimoncard.com
Lv.3 Gomamon P-004 P Rookie | Vaccine | Sea Beast - --- Inherited: [Your Turn] [Once Per Turn] When you trash a digivolution card of 1 of your opponent's Digimon, gain 1 memory.
W
DCG Wikidigimoncardgame.fandom.com
Lv.3 Gomamon P-004 P Rookie | Vaccine | Sea Beast --- Inherited: [Your Turn] [Once Per Turn] When one of your opponent's digivolution cards is trashed, gain 1 memory.
JP
Official Japanese Card Listdigimoncard.com
Lv.3 ゴマモン P-004 P 成長期 | ワクチン種 | 海獣型 - --- Inherited: 【自分のターン】［ターンに1回］相手のデジモンの進化元を破棄したとき、メモリーを+1する。