I built Mama Murphys chair as she asked but it didn't show up like other furniture to build in workshop mode. I just heard the building noise and afterwards couldn't find where the chair went. Many game hours later I was at the Sanctuary Hills workbench and heard her asking for Mentats, I looked around and couldn't find her. Then I looked up. I saw her feet and the feet of her chair stuck in the ceiling just above the workbench. I can talk to her but I can't give her the Mentats, so her quest is now stuck. I tried getting her to get off the chair by talking/shooting/hitting her, didn't work. I built stairs to the roof and I can't get close enough to her because of the junk up top. Very frustrating.