[Trexmaster]

Yeah, I've had instances where the game denied my input long enough to force me to auto-fail a QTE, or denied one or two keys, thus resulting in the input it -did- recieve to be inaccurate, thus, again, causing a failure I had little control over. (I.E. I get an up left right QTE, hit those keys, then it denies my up and inputs left and right, causing two failures.)

Even a short lag spike can be enough to jump-start the countdown to the point where it receiving all your inputs in time just isn't possible, or, if it does get any, they're either not the right ones, or it didn't receive enough of them.

If all else fails, just make the timer slightly longer than what it currently is (5 seconds seems fair to me).