A strange light has been reported shining near Perdida every evening. It can only mean there's a monster nearby.
This bounty is available to complete after obtaining Tengri.
You can find the Dualynx on the northwest side of the Autumnia continent; simply follow the mountain trail from the northwest beach to its end. It is accompanied by three lesser Auroralynxes, but since they have healing powers, its best to dispose of them first. Start off with several group attacks, then pick the lesser lynxes off one by one until only Dualynx is over, at which point the battle should be a breeze.
Defeat them and you'll complete the bounty hunt, return to the Swift Solutions to claim your reward.