This might be overthinking it but maybe getting this item has something to do with time it got decrypted. Just look at the name itself. If you play late night it would make sense this has a chance to drop. OP do you remember what time of the day you decrypted this or when the engram dropped? Edit: This might be a stretch but if you got the engram on the game that was at 530pm that day and decrypted it might actually be how to get one. Just look at the Tower as well, Twilight by definition is "the soft glowing light from the sky when the sun is below the horizon, caused by the refraction and scattering of the sun's rays from the atmosphere". I don't know like I said it's a big stretch but maybe have something to do with it. Unless of course the other guys decrypted it at different times/tower settings then it's meaningless. I'm basing all this off UTC. When it's 530 here it's midnight there...