I am using Photoshop CC (v 20). As of the new update, when I attempt to duplicate a single layer or group of multiple selected layers, the duplicated layer(s) are re-positioned outside of the canvas. I must drag them back to the correct location on the canvas.
If I attempt to duplicate multiple selected layers at once in my layers panel, Photoshop will place them at the top of the layers panel and outside of the artboard the original layers are located in.