Same issue here on BFV, it started after the anti-cheat update released on the 11th, no changes on my end between then and my last session.
On the first day just about every key caused a stutter, then in the following days somehow it got a little better on its own. Which keys are affected seems to change every time I start the game, sometimes WASD are fine, other times A and S stutters, and other times again it's just S.
I have RTSS running, closing it down only makes the stutters less severe, but they're still there and noticeable (from ~80ms stalls to ~40ms). I've also tried to disable any overlays and close down any unnecessary background programs (including the keyboard manufacturer's software) and it made no difference at all.
The "keypress buffer" workaround suggested in the comments here doesn't work for me, I can go from turning my PC on to joining a server using only the mouse and it's still the same keys to be affected (plus or minus a few buttons depending on the usual randomness).
Repairing the game replaced 3 anti-cheat-related files in the install folder, but I get the feeling that's normal behavior since those files get modified on first launch. I've also deleted the anti-cheat's cache found under %AppData% and it made no difference.
For what it's worth during my testing I noticed this issue can affect any keys, including the ones not bound to any in-game actions, and also the stutters do not occur when alt-tabbed out of the game.
The anti-cheat gets updated about twice a month on average, but with the holidays in between I get the feeling we won't be seeing a fix until at least mid-January. 💀
