I'm running AP version 1.67 and find the smudge tool works properly most of the time but does produce artifacts which cannot be blended out to a smooth transition.
The only solution, I have found, is to add more paint to cover the anomaly generated by the smudge brush. Your thoughts.
View screen capture. Even though in the screen capture the bottom layer is selected , actually the problem showed up as I worked the top pixel layer. After the artifacts showed up on while I worked the top pixel layer, I then ran through the layer stack to see if any subsequent layer was impacting the top layer's performance and that is when I took the screen capture with the bottom layer selected. Again the smudge issue is with the top layer.