It seems that something went wrong with drivers 17.4.x, and VSR resolutions doesn't show up in games, only in desktop environment.
Can you please confirm the issue? How long will it take to rectify it?
Honestly, I think it's quite serious as the new RX 500 series is only supported from 17.4.3 on-wards.
Some community feedback:
Anandtech - AMD Releases Radeon Software ReLive Crimson Edition 17.4.1 - April 06, 2017
VSR isn't working in this edition first time I've ever encountered this issue, it works in display setting in desktop but doesn't go past 1080p in my games - Ghost Recon Wildlands, SW Battlefront
AMD community thread - Can't get VSR to work properly on my RX480 - Apr 25, 2017
(VSR) Not working in any of the 17.x.x drivers and I haven't gone back any farther.
Currently on 17.4.3
reddit - VSR not working in games - Apr 26, 2017
I am unable to use VSR in games I previously could use them in. This happened after the windows update I'm starting to think. I went a few driver updates playing only games where I don't use VSR, and did a clean install when windows released their most recent 1703 update.
I can enable VSR in the AMD control panel, and can make my windows desktop resolution 1440p and 4k like normal, but no fullscreen games will show me options for increasing resolution past 1080p (my default monitor).