I was only about to get 1600x900 as the highest resolution when cycling through the options in game.
Topic on Talk:Harry Potter and the Order of the Phoenix
I should've added that the page currently reports 1080p as the maximum supported resolution.
I can select 1920x1080 in-game. It must be a problem on your end.
Thanks for the info. I am in 1440p so I wonder if it causes some problem in detecting compatible resolutions. I will post back here if I figure out a fix for any others.
To any future others also having this issue, the monitor I am using is also GSYNC.