Now I looked closely and saw it. When 3D transition to another scene, the picture slightly loses details (soft or light blur), you can movement panorama, BUT without using zoom. Look closely. However, when you make a small zoom (it does not matter - out or in), you notice that the detailing has appeared. I tested it on different versions (available to me krpano.1.21 / 1.21.2) everywhere the same thing. With a normal transition, for example, just blending, such an effect of "light softness" with loss of detail does not occur...
Maybe it's just me... I suggest you carefully test such an artifact on your desktops