This is an old thread, but this bug is still happening today on BF4! I'm this close to giving up and deleting BF4 Premium and forgetting BF Hardline. I have tried everything and I can't stop this happening about 1/4 times I'm moving whilst shooting. COD AW, TitanFall, Killzone no problem. I've resorted to having to fire and not moving as that's the only thing that seems to help. As soon as I run and shoot and have multiple buttons presed, you can bet this happens seemingly randomally in close quarters.
I play BF4 on PS4 with two different contollers, and both are the same, both new. I can't seem to repro it on the test range at all, only in hectic combat so far when the enemies are close. I thought it was me pressing too hard on R3, like some posters here, but I'm now not convinced as BF is the only game I have that does this.
It's possibly the R3 stick pick-up is too sensitive? Could an increased dead zone be added to advanced options? If it can't be fixed that way, then ideally, I'd prefer to be able to turn off the R3 action fully and have the knife as a double tap only, on another button and see if that helps. I also don't like the way the knife stays out if you hold R3 down, as that's not much use most of the time. I think for that, it would be best you hold, say hold down triangle for 4 secs instead.
The only two choices you have is:
DEFAULT - Knife comes out in melee when firing.
VETERAN - I crouch and lose time firing when in melee.
Both usually mean you die in a lame way.
ITS A GAME KILLER PLEASE FINALLY FIX IT OR PRESENT AN ALTERNATIVE!
Great game, but an enjoyment killer bug.