After some investigation I think its related to the way EPIC calculates the position of the spring/camera. The method’s math is based on your framerate and works well if it is stable (which is a bad assumption as framerate always drops somewhere even for a fraction of a second). If the frame rate fluctuates too much the positioning of the camera can be incorrect for a frame or two hence the stuttering. If you set a histogram based on the framerate you will notice that there is a direct correlation to ‘strong’ fps fluctuation and this stuttering effect although I noticed sometimes only a ~3fps fluctuation is enough to cause the problem.
In other words the stutter you see is not directly because of framerate fluctuation which mostly goes unoticed by our brain but its because the math to position the camera assumes a certain framerate to know where to place the camera and sometimes that assumption is wrong, it has nothing to do with your graphic card or drivers and everyone is affected by it if the conditions framedrop+enough speed to notice it are met.
It would be great if Epic could change the way they handle the update rate, I also love the effect!