When using scopes that have variable zoom, zoom in vehicle turrets, or even using zoom in soldier view it is very unresponsive. It sometimes rarely works the first time you click + or -. It requires multiple "spamming" of the keys to work. I've had it take upto 30 times of pressing the button to get it to toggle.
I know there are others users having this issue, everyone I play with regularly have reported it as well as a recent twitter user responding to the last sit rep of the year tweet.
This bug to me is a little more than minor, it significantly affects game play, at least my style of play.
If you are looking to recreate it, I gave noticed on low population or private servers it does not always occur,but on full and high population servers it has dominated the game.
Thanks for taking the time to recieve community feedback!