BTW I am sure that this change in 15002 is the source of the problem. I wonder if you can turn this new feature off?
Desktop Icon Placement and Scaling Improvements: We’ve heard from you that sometimes desktop icons aren’t scaled or arranged as expected, particularly after docking/undocking your device, working with monitors that have different DPI, or projecting your monitor. We want users to feel that desktop icons are stable, scaled properly, and move predictably when changing monitor configurations, so we’ve made changes to how this logic works in order to address your feedback. Now when you change your multi-monitor configuration, dock/undock your device, project your display, add or remove monitors, or otherwise make changes that affect the icon scaling, you should see an improvement in how the system adjusts the layout of your desktop icons. Try it out and let us know how it goes!