Strix Serenade should end up in my graveyard when destroyed from my library but it doesn’t.
Destroy
A card is destroyed either when it loses all of its toughness/shield counts or when another effect or spell demands it to be destroyed. When a card is destroyed, it is moved to the Graveyard. Cards that were exiled don’t count as “destroyed”. Also, effects that trigger when a card is destroyed only happen if it’s destroyed while onto play, and not if it was destroyed while on the library or hand.
You can see in the following image that every time I cast Traumatize and target myself that Strix Serenade is triggering off of being destroyed from my library, which isn’t supposed to happen according to the rules for destroy.
