Thanks, fixed it. the preset was 3840 x 2160. I think a lot of games have a Feature where if you don't hit confirm the resolution resets because of this issue.
Viewing post in Unplayable bug/Something that could use a fix
Yeah, I'm gonna add one of those, but it auto-detects your monitor's supported resolutions so it should really never be a problem. It's especially a problem because I default it based on those supported resolutions, and some people have the problem immediately before they can set it (although hard to tell how many of those reports are from before the auto-detect feature was put in)