When I trying to group 2 or more shapes on a vector layer, they disappear and causes visual glitches.
Actually they are still there and selectable, but not visible.
When I select a group of shapes I can see bounding boxes. When I ungroup it, shape are visible again.

Reproducible: Always

Steps to Reproduce:
1. Create new image and Vector Layer on it.
2. Select Freehand Path Tool, set Fill to Patern/ Also select some pattern
3. Draw 2 shapes
4. Select them and Group (in the tool options).
5. Move group around and deselect it

Actual Results:  
Visual content of group is invisible until you ungroup it.
Old contents of group are still in old location, image doesn't get updated until you ungroup shapes and move them over old location.

Expected Results:  
Grouped shapes should be visible.
Image should get updated after I move a grouped shapes.

Also try steps with path tools with Fill set to Not Filled.
I run Krita x64 on Win 8.1 x64.