So it seems not only Unreal editor but I get this issue with some games too. If using the Windows scaling feature it affects the resolutions and when creating a new editor windows (PIE) and I set it to be 1920x1080 it seems to save but when I hit Play and close the resolution has changed and now the number is something different and even changes and it is not constant. When I switch Windows Scaling off and relaunch the project everything works fine. Any idea? Anyone working on Ultrawide? I am using a 3440x1440 screen.