I've been taking a lot of screenshots in Fallout 4 lately, today when I started the game up, and got to somewhere I wanted to capture a screenshot, I pulled the console up, typed in fov 45, as I wanted a lower FoV for this particular image, the field of view changed as it should, and then when I closed the console it snapped back to default. I've not had this issue before, I've always been able to type in my desired field of view and have it remain, but not anymore it seems? Also tried on a different save where I've never modified the FoV via console, and tried deleting and generating new .ini files in my games folder. Would anyone know why this is happening?

Alright, found a solution. No idea why this is the case now, but typing in "fov xx xx", so for me "fov 45 45" works. Thanks to reddit user MoneyMan195 for figuring this out.