Highspeedg8r's solution to clearing the quest 'Princess Dea's Cousin'
I’ve figured out how to reproduce the issue and how to clear it properly. After you talk to Mandy, you have to speak to Dea again, then speak to Dara, and then go to Dyah and save Tari. If you go straight to Dyah and save Tari, you will be unable to clear the quest and Dea has no dialogue for Tari. You also can’t get the calming staff from Dara unless you talk to Dea first. Because I already had the calming staff it was easy to skip talking to Dara which could lead to the quest not clearing. I know this is an old thread but hope it helps for future players.