Thanks for your reply.
I disabled my ad blocker and that seems to have fixed half of the issue, now when I select a field, it changes it. But when I save it and reload, it still shows 'Hdeg 4:3'. I tried it on another browser (Edge) without any extensions as well, same issue. I deleted all my entries and tested on both browsers, still same issue.
No, only seems to be happening to 'FOV Type'.