My Video Card Is Nvidia Geforce GTX 660 Ti with the lastest game ready driver, here is the log of my system on directx diag so you can get all the details about my system:
Steps To Reproduce The Bug:
1- Create a New Third Person Project on 4.15
2- Go to project settings > Rendering > Optimizations > Clear Scene: set to clear at a far plane.
3- Restart the editor and compile Shaders
4- Move The Camera Around
I tested your steps on two separate machines, one of which was using an Nvidia GTX 660, but neither produced the results you are reporting. This seems GPU and driver specific, but to be sure would you test in a different version of the engine. If it also occurs there, then it is more than likely your card and not a bug with the engine. Maybe try going back to your previous driver to see if that has an effect as well.
Let me know if you have further questions.