So this is probably an SDL thing and maybe a "my computer is just weird" thing, but when I press this laptop's Fn key and press the function keys, I get unexpected results from love.keypressed.
For example, when I press Fn and F1 (which is mute), I get the key "d" (the scancodes are the same as the keys for all of these). It doesn't output the letter "d" in other applications though. Volume down and up are "c" and "b", numlock and scrolllock are as expected, display switch is "lgui" and search is "f14".
Weird. I've never heard of that before - but it's not something love's code can really affect, in any case. (It'd be up to either SDL or the operating system APIs that SDL calls).
I have a similar bug on Linux, except it affects everything and the key is never released, meaning that it leads to stuff like ddddddddddddd typed all over what I'm doing.
lf = love.filesystem
ls = love.sound
la = love.audio
lp = love.physics
lt = love.thread
li = love.image
lg = love.graphics