Hi,
A small bug I've noticed with FSAA that can be reproduced 100%, on different machines too. Tried with nvidia 980 ti, 1080 ti, win 7 64 and win 10 64 so far. Different nvidia driver versions used as well, no change. Vanilla Arma 3, no mods.
I've only noticed this bug with edges over water so far but it's possible it can be present elsewhere in the game. Basically FSAA creates a kind of aliasing with bits of white. See picture at the bottom of this post - I put some red marks next to where the glitch is most visible.