Very odd Timelapse issue

I have a 1080p IP security camera that has taken some very cool timelapse. So now I want to try it with my Nikon D3300. The first 4 tests have all had a very peculiar issue. At random intervals a frame will "jump up" a few mm's. I'm uploading 2 images so the issue can be seen. VR on the lens is off and the last test was done inside to eliminate the chance of freak wind gusts moving the whole camera.
Centre bottom of the images is a plastic jar with white lid. Compare the label in both images to see the issue. It does not look much but produces a horrible jump in the video.
Anyone familiar with Nikon D series who may have a suggestion for more settings that might affect the camera this way. Lens VR is off. Could the mirror be causing this and if so can I lock in place?