I guess they even fixed it? I think the Checkbox ‘Mipmap Level’ in top of the window controls the displayed Resolution for the preview. So it is the 1024x1024 resolution you see in the 4.17 example. Your ressource size is 1.2mb in the 4.17 example and 341kb in the 4.16 example, maybe there is some problem too?
Also, do you know what the ‘LOD Bias’ does? It just seems to lower the max in-game resolution and addds to the combined LOD Bias count.