Photoshop :: CS6 Extended Load / Replace Texture Command

In the 3d Materials Panel in Adobe Photoshop Extended CS6, the REPLACE TEXTURE and LOAD TEXTURE commands for the 3d materials seem to create a single  "smart" texture that all other textures created via the "replace/load texture" commands link to.
 
For instance, to texture a sphere using a Photoshop file, I first created a file called "horizontal stripes for 3d peel.psd" and saved it on my desktop. I went to the Materials Panel>Diffuse>(Clicked icon to right of "Diffuse") and chose "Load Texture>"horizontal stripes for 3d peel.psd," to apply it to my sphere.  I then edited this diffuse file by right-clicking the icon to the right of "Diffuse," choosing "Edit" and adding a color layer at the top of the layer stack, then saving (not saving as) and closing the Diffuse .PSB smart object  file.
 
I then loaded a texture to the Opacity material of my sphere using the same Photoshop file on my desktop called "horizontal stripes for 3d peel.psd", going to Materials Panel>Opacity>(Clicking the  icon to the right of "Opacity") and choosing "Load Texture>"horizontal stripes for 3d peel.psd,"  When I opened this file to edit it by right-clicking the icon to right of "Opacity" and choosing "Edit," I found I'd loaded not the original file on my desktop that I had chosen, but my edited "Diffuse" file. Furthermore, these Diffuse and Opacity files appear not to be independently editable--they behave like linked Smart Objects, and when one is edited, the other is updated with the changes.
 
Is this a bug? I can't find any mention of this behavior in the Photoshop User Manual. I'm using Windows 7, and I get the same behavior on 2 different computers with Photoshop. [URL].........
 
I had hoped to use the Load/Replace texture command as a quick way to load up independently editable versions of the same file to the different 3d material attributes (opacity, shine, etc.), but that doesn't seem possible.   Or is there a better way to do this?