Not really sure where to post this discussion, as it could be under both this and multiple other quests... but Karliah glitched away from the Nightingale Hall during "Trinity Restored" and was teleported back to the Snow Veil Sanctum, back waaaay where she was when she shot you with her arrow. She was stuck in the gate leading back outside to Skyrim. When I spoke to her, it was what she was meant to say at the Hall. ...After I left the Sanctum through the back door, my vision got all blurry and I collapsed, and "Speaking With Silence" was started up all over again.
I had to talk to Karliah all over again, talking about Mercer's betrayal and why she shot me with a poisoned arrow. That whole particular quest repeated, now it's on my completed quest log twice. I'm just so thankful I didn't need to to any other the quests in between that one and Trinity Restored... I'd ragequit if I needed to go through the dwemer museum again and do that stupid charcoal thing again...
Has this happened to anyone else?