I learned a very simple - yet so important - tip today, for processing HDR images in the new Lightroom CC/6.
Pay close attention to the FIRST image you select in your series.
The reason is that Lightroom seems to use that first image (referred to as the "most selected") as a reference point when it comes to distinguishing changes, like movement, in the scene. For example, take a good look at the two images below. Look at the water surface. These two HDR images were made from the same 4 original frames, and processed in exactly the same manner. But the lake surface is noticeable smoother in the image on the left.
Because in that leftmost image, I selected the longest shutter speed exposure first, before selecting the other three images for the HDR.
The image on the right, is the result of me selecting the shortest exposure in the series first.