I finished "Hard Answers" after speaking to Enthir and Karliah at the basemant of The Frozen Hearth at Winterhold. Karliah rewarded me with the Nightingale Blade and then told me to meet her at the Ragged Flaggon. Supposedly I was to receive "The Pursuit" quest after I was told to meet Karliah at the Ragged Flaggon but I didn't but I tried to meet her there anyway. I went to the Ragged Flaggon and she wasn't there so I made my way all the way through the Ratway and still couldn't find her. I received no quest so I tried doing extra work from Delvin but still couldn't initiate the quest.

Does anybody know what's going on? Does it have something to do with me making a duplicate of Brynjolf? Or does it have something to do with one of the mods I've installed?

same bug here, karliah can be found in the Winterhold pub basemant not responding to action.
Hoped to find a workaround here^^

found in another thread: http://www.uesp.net/wiki/Skyrim:The_Pursuit