What is it? Why the camera in the “perspective” spontaneously moves?
and it is not in the same project, checked a couple of projects
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Maybe there is a camera actor somewhere on the map, and it got animated with matinee?
But you are not even playing, well that is odd, maybe your mouse sends some input, maybe something with your mouse? Turn the mouse up side down and see if movement happens.
Hmm … in itself is a “phantom movement” stopped.
Cameras in the project and no matine
Make sure that you always disconnect all controllers (xbox,…) 
Yes, the controller was connected. Sorry for panic 