Ah right. As I explained earlier, in order to run HTML5 projects, browsers require that you run from a server (local files are almost always blocked). For this Fusion sets up its own internal web server and then serves the web page with your files in it. I don't know whether it checks for the latest files for this process when doing so, but the connection you saw is related to this and nothing untoward.
The issue with your jumpy animation relates to the hotspot (what you termed the pivot point). Unless the hotspot is set to relatively the same perceptual spot on your image, it will appear this way. If you crop all images and this results in different shapes, simply centering the hotspot (which is the offset the image is drawn at) did not guarantee that it will be in the correct place.