There are some 3D display bugs arising from the bad programming practice of threads. To be fixed soon. However there might be cases where the heuristics used for grasp planning my fail. The precision grasp is the most dependable then comes power grasp. The least dependable heuristics is the one for side grasp.
Improvements is underway.
The recognition depends on pre-trained network weights. The training employed tried to cover whole space of actions. However you may find regions where the training did not do very well.