I seem to be experiencing the same issue. It seems to happen more near the top of a page than near the middle/bottom and only when zoomed in, with drift on or with the anchor set (i.e. not drifting). It seems to go away at times, but is a little hard to recreate intentionally. When it does happen, the ink displacement is up and to the left. Happens with wrist guard on and off; set to the middle right-handed mode when on. I'm currently using a "dumb" stylus w/ rubber tip (the ~6mm wide variety). I'm on an iPad 2 running iOS v7.0.4 and Penultimate v5.0.1. I'm a long-time Notability user and have been researching styli with the intention of buying a newer, better stylus than what I'm currently using. My search made me aware of the new features in Penultimate so I decided to re-download it on the iPad and give it another try. The new drift feature takes a bit getting used to, but the misplaced ink location from the apparent bug make it unusable for me. I will keep it installed in hopes the the bug is fixed and I can give the app a fair try.