Hi, everyone!
Yesterday I was playing at my local card shop. I was using RDA and my opponent was using Dracotail.
They summoned Arthalion using a card from the hand, then they tried to target their Effect Veiler in their Graveyard to add it back to their hand.
When they activated Arthalion's effect, I chained Fidraulis Harmonia's effect (show 5 Synchro Monsters, send 1 to the Graveyard, pop 1 card, summon Fidraulis, bounce 1 card with Malong, since it has been sent to the Graveyard).
I targeted the Arthalion for my pop effect and another card for the bounce effect. My idea was to prevent Arthalion from activating its effect in the first place.
My opponent argued that, since it's their turn, Arthalion's effect activates BEFORE Fidraulis' and, since they now have an Effect Veiler in their hand, they can chain it to my Fidraulis, thus negating the pop.
So, instead of ending up with Arthalion and Veiler in the Graveyard and a bounced card, they would end up with Arthalion and that card still on the field, and Veiler in the graveyard (since it was used to negate my Fidraulis).
This explanation didn't really sit well with me, but I just wanted to play the game instead of arguing, so I didn't really push back on that interpretation.
Is my understanding of this card interaction correct?