[Solved] Serpent's Ire: no Twin's Grieving Insignia recipe?

Does anyone have a clue why I did not receive The Twins' Grieving Insignia upon completing Serpent's Ire?

Was it because I ported to the next WP shortly before the event was done? (I had died, that's why I ported, and I did not get back in time to the location of the last fight before it ended.)

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Edit: Okay, apparently three drops are random, including said insignia.