here it is clear
Strange, it works on my side. Are you using the latest Fiji?
When you first launch the 3D Viewer, a dialog box appears. One of the options is called resampling factor, and unfortunately the value defaults to 2, which I think tells the 3D Viewer to combine each block of 2x2 pixels into a single voxel. Did you try changing it to 1? Maybe then things will work.