Summary: In the chaos of the later Thieves Guild quests, I never managed to speak to Maven about Vald's debt, and therefore never started the quest for the Quill of Gemination before dealing with Vald. Unfortunately, I can't seem to get rid of the quest to clear his debt now.

At any rate, I noticed the quest step "Speak to Maven Black-Briar about Vald's debts" blinking at me in my journal, so even though I had already dispatched Vald and completed the main quest line for the guild, I set out to strike it from my journal (I hate a messy quest log filled with incomplete tasks); Maven readily tells me about the quill and to go for a swim in the lake to find it, so I do so. Snatch the quill, run back, find Maven, and to my surprise it's like she doesn't realize I'm throwing the quill in her face. There's simply no option to give it to her and complete the quest. In addition, since the item is marked as a quest item, I can't drop it and hope she notices.

Has anyone else run into this issue? If so, is there a fix?