Hi @lowhues!
Spyndel says lots of stuff. I wouldn’t pay him too much attention 
However, before we change the subject I’ll just mention that your tool does indeed look small against the floor grid. For reference I was speaking about the Tool> Geometry> Size> XYZ size. A size of approximately 2 is considered ideal. Drastically larger or smaller and you may encounter issues. An especially small tool would be one that is under an XYZ of 1.0.
I don’t immediately think this would be your problem. It would be more likely to have to do with an extreme offset from center. When imported correctly ZBrush adjusts for off-center meshes and re-centers them in the worldspace, then returns them to their original position on export. Sometimes though when a mesh is imported with a really drastic offset from center this can cause problems. Likewise if the pivot for the mesh is not centered, this can cause the mesh to behave erratically when navigating with it.
I do notice that you are zoomed in close enough to have activated Auto Crop mode for the camera. This is indicated by the lit “AC” on the top right edge of the UI window frame. What may be happening is that your mesh is small and it is forcing you to zoom in problematically close, which triggers AC and may change the viewport behavior.
Further information on Auto crop can be found here:
Universal Camera | ZBrush Docs.
Try zooming into the mesh just shy of activating that “AC”, and see if the problem still occurs. If it does not, it may be related to Auto Crop. You may also wish to switch off perspective mode and see if that helps.
Otherwise, try restarting ZBrush and load the Dog.zpr from Lightbox. If the problem does not occur in that file when none of the settings for the problem file have been loaded into the program, you can be fairly certain the problem is related to the Tool you are working with and its relationship to the world space.
