Hi Pat - thanks for having a look. View is at Oº and is the right way up. In the screen grab attached, you can see when I select and move the objects 45º up the Z (and along the X) axis the object doesn't move with the smart cursor to the end point of the dotted line like it should, it shifts along the X axis. When I release the mouse click it's where it should be.
The view is front orthogonal 0º rotation in screen plane view. It happens in other views as well though. Snap to grid and snap to working plane are not selected.
Looks like it's snapping to a working plane somehow but none are set that I can see?