Audi ACC is great, but the lane keep assist is quite "bouncy" and will ping-pong between left and right lane barriers and will self-disable after a few of these.
I think this is by design. My Subaru does this too. My feeling is that it’s an emergency feature meant to keep you on the road, not something you should rely on to steer the car completely, so they don’t want it to be too good. The quicker jerk back into lane is also enough to grab your attention, and bring it back to the wheel.