Dangerous Love seems to be a breadcrumb on the same level as the three Dearest Elenia quests, as Fenstad immediately offered Fenstad's Hunch after I completed the Orgrimmar version of Dearest Elenia. Instead, it was marked as available in the Quests by Zone tab until I finished the final quest.

https://classic.wowhead.com/quest=8904/dangerous-love

Version 6.2.5

EDIT: This is apparently a Horde-only bug: see the end of this article https://classic.wowhead.com/guides/wow-classic-love-is-in-the-air-holiday-event