support.chaos.com "submit a request" would be the way to go, as a copy of the scene (you can delete the prototype, or otherwise simplify the scene down to just the bare bones problem objects that show this difference) would be very useful (and that's the secure, private way to send in a scene copy now). We'd also need which version of C4D, which OS and version. There weren't any changes to lights or rendering calculations in HF 1, so without seeing more of what is going on in the scene, we wouldn't be able to identify what might be the cause of this. All the changes in HF 1 can be seen here
https://forum.corona-renderer.com/index.php?topic=37006.0 and none of them sound like anything that would cause a change in lighting.
On the original displacement jumping, if the camera was moving it is best to use World and not Screen displacement, as screen saves memory by doing less subdivisions and detail for more distant objects, which means if a camera is moving then displacement can change from frame to frame; Render Settings, Corona, Performance has the option to switch over to World for displacement calculations, which does not vary the displacement based on distance from camera. That would be worth a look to see if it solves the jumping displacement.
