encountered numerous glitches with these quests. First was during step into her shoes, after going through the portal you don't get credit for going through the portal.
I fixed this with a simple logoff and login.
Second is during saving nine. after closing all but one of the portals and accepting the quest, the last remaining portal disappears. I haven't been able to fix this one yet. I've tried turning off all addons, dropping the quests, walking a good distance away. exiting. everything I could think of. If you encounter this you may need to open a ticket.
edit: I received a response for the ticket I opened about this. Blizzard has not yet decided to mark this quest for autocomplete. They have received numerous reports, and the bug team is working on it. In the meantime they suggested links to wowhead where other players have commented possible workarounds. :) You guys.... they linked me to my own comment XD
So to update, if you drop, repickup at boralus, and make it back to the island, some have reported to be able to take the rift. If it is still glitched and not showing up, we currently have no fix, and I expect we wont have an update until the next maintenance.