As of 1.24 inception there is a intermittent bug, that if mess with anything in game options especially controls sensitivity settings will intermittently default field of view to default which is half way on slider bar.
I play max field of view on slider bar and this bug gets very annoying if messing with options.
The bug is so weird and inconsistent that sometimes it will revert field of view slider bar to default halfway but still have you set to max field of view visually while playing not in men other times will set you to default visually.
My suggestion would be either fix bug or just default field of view to always max on slider bar.