Bug 1. If you Ctrl-shift-select not only you can select subobjects of the object you click on, but you can also select the object, if it’s inside a group. This nugget is not happening if the object sighing a group is a SubD object. You can only select its subobjects.
Bug 2. If via sub-selection you try to select a face that’s parallel to your view, like the bottom face of a cube when look from the front view, you cannot select that face. You can only select edges.