My brush healing tool in CS6 is leaving a texture trail instead of smoothly blending edges. I have the "sampled" icon checked, not the"pattern" icon. As far as I am aware, I have changed no settings since I last used this tool successfully. I have reset the tools, to no avail. The trail has dark and light spots in it. I have all the latest updates. I am running on a Mac Pro with 16GB of RAM. Suggestions?